Property Tax Estimator Calculator — How Much Will You Owe in 2026?

Property taxes are one of the most significant and least understood costs of homeownership. Unlike your mortgage payment, which is fixed at closing, property taxes fluctuate with your home's assessed value, your local government's budget needs, and the tax rates set by multiple overlapping jurisdictions — county, city, school district, and special assessment districts. For many homeowners, property taxes represent the second largest housing expense after the mortgage itself, yet most buyers estimate them loosely or not at all before making an offer.

Our Property Tax Estimator Calculator gives you a clear, accurate projection of your annual property tax obligation based on your home's market value, your jurisdiction's assessment ratio, and the mill rates levied by the taxing authorities in your area. Whether you are evaluating a home purchase, planning your annual housing budget, appealing an assessment you believe is too high, or comparing the tax burden across different neighborhoods and counties, this calculator gives you the numbers you need before they show up on a bill.

This guide explains exactly how property taxes are calculated, what determines your bill, how assessed value differs from market value, how mill rates work, where the money goes, and what you can do when you believe your assessment is wrong. Understanding every component of the property tax system is the foundation of intelligent homeownership budgeting — and it starts here.

What Is a Property Tax Estimator Calculator and Who Needs One?

A Property Tax Estimator Calculator is a tool that projects your annual property tax bill by combining your home's value, your jurisdiction's assessment ratio, and the applicable mill rates from all taxing authorities in your area. It translates the abstract machinery of local government finance into a concrete dollar figure you can use for budgeting, purchase decisions, and financial planning.

Every prospective homebuyer needs one before making an offer. Property taxes vary so dramatically across locations — from under $1,000 annually in low-tax states to over $20,000 annually for the same home value in high-tax jurisdictions — that buying without knowing your tax obligation is a serious financial planning error. A home that appears affordable based on its purchase price and mortgage payment can become genuinely unaffordable once the true property tax burden is factored into the monthly housing cost.

Existing homeowners need the calculator when their assessed value changes — which happens after purchase, after major renovations, and periodically through mass reassessment cycles. Investors need it to accurately model operating costs on rental properties and evaluate cap rates. And anyone considering relocating between states or counties needs it to compare the true all-in housing cost across locations, not just the sticker price of homes.

How Property Taxes Are Calculated — The Complete Mechanics

Property tax calculation follows a consistent formula across the United States, even though the specific numbers vary dramatically by location. Understanding the formula lets you verify any estimate, check your tax bill for accuracy, and understand exactly what is driving your tax obligation. The formula has three components: assessed value, the mill rate, and any applicable exemptions.

The basic formula is: Annual Property Tax = (Assessed Value ÷ 1,000) × Mill Rate, minus any exemption reductions. Each component of this formula is set by different authorities and can be challenged or adjusted through different processes. Knowing which component is too high — and why — is essential before you can take any action to reduce your bill.

Market Value vs Assessed Value — Understanding the Difference

Market value and assessed value are two different numbers, and confusing them is the single most common source of property tax misunderstanding. Market value is what your home would sell for in an arm's-length transaction between a willing buyer and a willing seller — essentially, what the market says your home is worth. Assessed value is the value your local assessor assigns to your property for tax purposes — and it is frequently different from market value.

Most jurisdictions assess property at a fraction of market value, called the assessment ratio or assessment level. A jurisdiction with a 70% assessment ratio will tax a $400,000 home on an assessed value of $280,000. A jurisdiction with a 100% assessment ratio taxes the full $400,000. Some states and counties use ratios as low as 10% to 25% of market value — which sounds like a massive discount until you realize they compensate with proportionally higher mill rates.

The Property Tax Estimator Calculator accounts for your jurisdiction's assessment ratio automatically when you enter your location. This is why entering location data accurately is critical — a calculator that applies a 100% assessment ratio to a jurisdiction that actually assesses at 70% will overestimate your tax bill by nearly 30%. The assessed value printed on your tax bill is the number that actually matters for your current obligation; market value is what you need to estimate future taxes as your home appreciates.

What Is a Mill Rate and How Does It Work?

The mill rate — also called the millage rate — is the tax rate applied to your assessed value to calculate your tax bill. One mill equals $1 of tax per $1,000 of assessed value. A mill rate of 20 mills means you pay $20 in taxes for every $1,000 of assessed value. On an assessed value of $280,000, a 20 mill rate produces an annual tax bill of $5,600.

Mill rates are not set by a single authority — they are the sum of rates levied by every taxing jurisdiction that has authority over your property. A typical residential property in the United States is subject to mill rates from the county, the municipality or township, the school district (often the largest single component), and potentially special districts for fire, water, sewer, library, parks, or other services. Each jurisdiction sets its own mill rate annually based on its budget needs and the total taxable value in its district.

Total effective mill rates across the United States range from under 5 mills in some low-tax Western states to over 40 mills in parts of New Jersey, Illinois, and Wisconsin. This variation — an 8x difference between the lowest and highest mill rates — is why two $400,000 homes in different states can have annual property tax bills of $1,200 versus $9,600. The Property Tax Estimator Calculator uses local mill rate data to produce an estimate that reflects your specific location rather than a misleading national average.

How Assessment Ratios and Mill Rates Interact

Assessment ratios and mill rates are inversely related by design — jurisdictions that use lower assessment ratios typically offset them with higher mill rates to raise the same total tax revenue. This means you cannot evaluate your tax burden by looking at either the assessment ratio or the mill rate in isolation. The only number that matters for comparison purposes is the effective tax rate: the annual tax bill divided by the market value of the property.

For example, Jurisdiction A assesses at 100% of market value with a 15 mill rate, producing an effective tax rate of 1.5%. Jurisdiction B assesses at 50% of market value with a 30 mill rate — the same 1.5% effective rate. Both homeowners pay identical taxes on the same market value home. The different assessment ratios and mill rates are just different ways of arriving at the same effective tax burden.

The Property Tax Estimator Calculator converts all inputs to an effective tax rate, which is the most useful number for comparing tax burdens across jurisdictions and for projecting your future tax bills as your home value changes. When someone tells you their county has a "30 mill rate," that number is meaningless without knowing the assessment ratio. Effective rate — taxes paid divided by market value — is the universal comparator.

Property Tax Rates by State — The Landscape of Variation

Property tax burdens vary more dramatically across U.S. states than almost any other component of housing cost. Understanding where your state and locality fall in this spectrum is essential context for interpreting your Property Tax Estimator results and for evaluating the true affordability of homes in different markets.

Low Property Tax States

Hawaii consistently reports the lowest effective property tax rates in the nation — typically around 0.28% of market value annually. On a $500,000 home, that is approximately $1,400 per year in property taxes. Alabama, Louisiana, Wyoming, and Colorado also consistently rank among the lowest property tax states, with effective rates generally below 0.5%. These states typically fund government services through higher sales taxes, income taxes, or natural resource revenues rather than property taxes.

Low property tax states are not uniformly advantageous — they often have higher taxes in other categories, and the lower property tax burden may be offset by fewer government services, lower-quality public schools, or other trade-offs. But for homeowners on fixed incomes, retirees, and anyone for whom the predictable annual cost of homeownership is a critical planning variable, low property tax states offer a genuine and significant financial advantage.

High Property Tax States

New Jersey leads the nation in property taxes, with an effective rate consistently around 2.2% to 2.5% of market value annually. On a $400,000 home, that is $8,800 to $10,000 per year — $733 to $833 per month — in property taxes alone. Illinois, Connecticut, New Hampshire, Vermont, and Wisconsin also rank among the highest property tax states, with effective rates frequently exceeding 1.8% to 2.0%.

High property tax states often fund excellent public school systems through property tax revenues — New Jersey and Connecticut, for example, are consistently ranked among the top states for public school quality. For families with school-age children who plan to stay in an area long-term, the trade-off of high property taxes for strong public schools may be worth it. But for empty nesters, retirees, or buyers without children in public schools, the tax burden represents a significant ongoing cost with limited personal benefit.

The Property Tax Estimator Calculator accounts for state-level variation in both assessment ratios and mill rates. Always verify your specific county and municipality — within high-tax states, there can be enormous variation between jurisdictions. In Illinois, for example, effective tax rates range from 1.5% in some downstate counties to over 3.5% in parts of the Chicago suburbs.

Texas and Florida — The High-Tax Exception in No-Income-Tax States

Texas and Florida attract residents with their lack of state income tax, but both states rank among the higher property tax states nationally to compensate. Texas has an effective property tax rate that typically runs 1.6% to 1.9% of market value — significantly higher than the national average. Florida's effective rates are more moderate at around 0.8% to 1.1%, but still higher than many income-tax states.

For buyers relocating from income-tax states to Texas or Florida, the no-income-tax benefit must be weighed against higher property taxes. At moderate income levels, the trade-off may favor Texas and Florida. At very high income levels, the absence of state income tax produces net savings even accounting for higher property taxes. The Property Tax Estimator Calculator handles the property tax side of this calculation — use it alongside an income tax comparison for the full picture.

What Your Property Taxes Actually Fund

Property taxes are the primary funding mechanism for local government services — and understanding where the money goes helps you evaluate whether your tax burden reflects the services you receive. Unlike federal or state income taxes, property taxes are almost entirely local in their collection and expenditure, making them a direct link between what you pay and what you receive.

Public Schools — The Largest Recipient

In most jurisdictions, the school district levy is the single largest component of your property tax bill — often representing 50% to 70% of the total. Property taxes fund teacher salaries, school construction and maintenance, administrative costs, and educational programs at the K-12 level. This is why school district quality correlates so strongly with property values — higher home values generate more tax revenue for schools, which improves school quality, which increases property values in a reinforcing cycle.

The school funding component of your property tax is set by the school board through a separate mill rate from the county and municipal levies. In states with strong local control over education funding, this component varies enormously between school districts. In states that have shifted toward more centralized school funding formulas, the school levy is more uniform across jurisdictions.

County and Municipal Services

County government levies fund courts, law enforcement (sheriff's department), county roads, public health services, social services, and county administration. Municipal levies — separate for homeowners within city or township limits — fund local police, fire protection, local road maintenance, parks and recreation, and city administration. Together, county and municipal levies typically represent 20% to 35% of the total property tax bill.

Special District Levies

Many properties are subject to additional levies from special purpose districts — fire districts, water and sewer districts, library districts, hospital districts, park districts, mosquito abatement districts, and others. These levies are often small individually but can add up meaningfully. A property in a jurisdiction with a county levy, a school levy, a city levy, a fire district levy, a library district levy, and a water district levy might have six or seven separate line items on its tax bill, each set by a different authority with a different budget and a different annual rate.

Special district levies are particularly important in rapidly growing suburban areas where new infrastructure districts are created to fund the roads, utilities, and amenities in new developments. Community Development Districts (CDDs) in Florida and Municipal Utility Districts (MUDs) in Texas are common examples — they add substantial ongoing tax obligations that can persist for twenty to thirty years after a development is built. The Property Tax Estimator Calculator includes special district levies in its estimates for locations where they are known and significant.

Property Tax Exemptions — Reducing What You Owe

Most states and many localities offer property tax exemptions that reduce the assessed value subject to taxation for qualifying homeowners. Understanding which exemptions you qualify for is one of the most straightforward ways to reduce your property tax bill — often substantially — and one that many homeowners fail to pursue simply because they do not know the exemptions exist.

Homestead Exemption

The homestead exemption is the most widely available property tax reduction for owner-occupied primary residences. It reduces your assessed value by a fixed dollar amount — commonly $25,000 to $50,000 — before calculating your tax bill. In Florida, the homestead exemption reduces assessed value by $50,000 for most homeowners, saving approximately $1,000 to $1,500 annually at typical Florida mill rates. Texas offers a $100,000 homestead exemption from school district taxes, a very significant reduction.

The homestead exemption is not automatic in most states — you must apply for it, typically within the first year of ownership and by a filing deadline that varies by jurisdiction. Missing the filing deadline means paying full taxes for an entire tax year before the exemption takes effect. The Property Tax Estimator Calculator can apply the homestead exemption to your estimate when you indicate that the property will be your primary residence.

Senior Citizen Exemptions and Circuit Breakers

Most states offer additional property tax relief for senior citizens, either through enhanced exemptions (additional assessed value reductions for homeowners over age 65), property tax freezes (locking in the assessed value or tax bill at the year a senior qualifies), or circuit breaker programs (limiting property taxes to a percentage of income for low-income seniors). These programs can reduce senior homeowners' property tax bills by hundreds to thousands of dollars annually.

Senior exemption availability, eligibility requirements, and benefit amounts vary enormously by state and locality. Some programs are income-limited. Some require a minimum period of residency. Some are available at the state level while others are locally administered. If you are over 65, contact your county assessor's office to find out specifically what relief programs are available in your jurisdiction and what the application requirements are.

Veteran and Disability Exemptions

Veterans — particularly disabled veterans — qualify for significant property tax exemptions in many states. Some states exempt disabled veterans' primary residences entirely from property taxation. Others provide partial exemptions scaled to the disability rating assigned by the VA. Active duty military personnel may also qualify for reduced rates or deferred payments in some jurisdictions.

Disability exemptions for non-veteran homeowners with qualifying disabilities are available in many states as well, though the programs vary widely in their eligibility criteria and benefit levels. If you or a household member has a documented disability, check with your state's department of revenue or local assessor for available programs. These exemptions are frequently underutilized because eligible homeowners are not aware they exist.

Agricultural and Conservation Exemptions

Properties used for agricultural purposes — farming, ranching, timber production, and related uses — often qualify for preferential assessment programs that value the land based on its agricultural use value rather than its development market value. These programs, called current use assessment, use value assessment, or agricultural preservation programs depending on the state, can dramatically reduce property taxes on rural land that has appreciated significantly in market value but continues to be used for agriculture.

Conservation easements — legal agreements permanently limiting development on land in exchange for conservation benefits — can also reduce property taxes significantly in states that provide tax benefits for easement-encumbered land. For rural property owners and agricultural landowners, these programs represent some of the most substantial property tax reductions available anywhere in the tax code.

How Property Assessments Work — The Annual Valuation Process

Understanding how your property gets assessed — and how often — is essential for anticipating changes in your tax bill and knowing when your assessment might be wrong. The assessment process varies by state, but the core mechanics are consistent across jurisdictions.

Mass Appraisal vs Individual Appraisal

Local assessors typically use a mass appraisal methodology to value thousands of properties simultaneously, rather than conducting individual appraisals of each property every year. Mass appraisal uses statistical models that apply market data — recent comparable sales, property characteristics, neighborhood trends — across entire categories of properties to estimate market values efficiently.

Mass appraisal is accurate on average but imprecise for individual properties. Statistical models cannot account for every property-specific characteristic — unusual lot shapes, deferred maintenance, superior finishes, unique features — that would affect an individual property's actual market value. This is why individual assessments sometimes diverge meaningfully from actual market value, and why the appeals process exists to correct those divergences.

Assessment Cycles and Reassessment Triggers

States and counties reassess properties on different schedules — annually in some jurisdictions, every two or three years in others, and on longer cycles in some states. California's Proposition 13 limits reassessment to sale events and new construction, meaning properties can carry assessed values far below current market value for decades if the same owner holds the property. This creates enormous disparities between long-term owners and recent buyers in the same neighborhood.

Major reassessment triggers across most states include a sale of the property (which typically resets the assessment to the sale price), significant new construction or renovation (which requires a supplemental assessment), and periodic countywide revaluation projects that bring all assessments in line with current market values. After any of these events, expect your assessed value — and therefore your tax bill — to be recalculated based on current conditions.

What Happens After You Buy a Home

In many states, purchasing a home triggers an immediate reassessment to the sale price. This means that if you buy a home for $425,000 that was previously assessed at $310,000, your new annual tax bill will be based on $425,000 — potentially a significant increase from what the prior owner paid. This reassessment-on-sale mechanism is one of the most important reasons to estimate your property taxes based on your purchase price rather than on the prior owner's tax bill.

The Property Tax Estimator Calculator defaults to using the purchase price as the assessed value base in full-assessment jurisdictions, which is precisely the right approach for buyers estimating their first-year tax obligation. Checking what the current owner pays tells you almost nothing useful if the property was last sold years ago in a different market environment.

How to Appeal Your Property Tax Assessment

Property tax assessments are not infallible. Mass appraisal models make errors, assessors lack property-specific information, and market conditions can shift faster than reassessment cycles can track. If your assessed value exceeds your property's actual market value — or exceeds the assessed values of comparable properties in your neighborhood on a per-unit-value basis — you have grounds to appeal and potentially reduce your tax bill permanently.

Grounds for a Successful Appeal

The strongest ground for a property tax appeal is demonstrating that your assessed value exceeds your property's fair market value. The most compelling evidence is a recent arm's-length sale — if you recently purchased the property for less than the assessed value, the sale price is powerful evidence that the assessment is too high. An independent appraisal from a licensed real estate appraiser showing a value below the assessed value is similarly compelling.

Inequity appeals — arguing that your property is assessed at a higher percentage of market value than comparable properties in your area — are also valid grounds in most jurisdictions. These appeals require assembling data on comparable properties, their assessed values, and their market values to demonstrate that you are being taxed disproportionately relative to your neighbors. This is more work to document but can be highly effective in jurisdictions with inconsistent mass appraisal models.

The Appeal Process

Property tax appeals typically follow a multi-step administrative process before reaching the courts. Most jurisdictions require an initial informal review or hearing with the assessor's office, followed by a formal appeal to a local board of review or equalization board, and then an appeal to state tax court if the administrative process does not produce a satisfactory result. Filing deadlines are strict — missing the initial appeal deadline typically means living with the assessed value for another full tax year.

For most residential properties, professional representation from a property tax attorney or consultant is not necessary for informal reviews and board of review hearings — many homeowners successfully appeal their own assessments with proper preparation. For high-value properties, commercial properties, or complex cases, professional representation typically pays for itself through the tax savings achieved.

Property Taxes and Escrow — How Your Lender Collects

Most mortgage lenders require property taxes to be collected through an escrow account — a lender-managed account funded by a portion of your monthly mortgage payment that the lender uses to pay your tax bill directly when it comes due. Understanding how escrow works prevents costly surprises when your escrow account is adjusted and your monthly payment increases unexpectedly.

How Escrow Accounts Work

Each month, you pay one-twelfth of your estimated annual property tax bill into an escrow account held by your lender. When your property tax bill is due — annually, semi-annually, or quarterly depending on your jurisdiction — the lender pays it directly from the escrow account. This eliminates the risk of a homeowner failing to budget for a large annual tax bill and defaulting on a tax obligation that could result in a tax lien on the property.

The lender performs an annual escrow analysis to compare actual tax bills against estimated payments. If your actual tax bill was higher than estimated — because your assessment increased or your mill rate went up — you will have an escrow shortage that must be made up either in a lump sum or through increased monthly payments. This is the source of the "my payment went up even though my rate is fixed" complaint that many homeowners encounter.

Escrow Cushion Requirements

Federal RESPA regulations allow lenders to maintain an escrow cushion of up to two months of escrow payments as a buffer against shortfalls. This means your escrow account typically holds more than the exact amount needed to pay the next tax bill — the cushion is the lender's protection against underpayment. Understanding the cushion requirement helps you reconcile your escrow account balance against what you would expect based purely on dividing your annual tax bill by twelve.

Using the Property Tax Estimator for Home Purchase Decisions

The Property Tax Estimator Calculator is most valuable when used proactively during the home shopping process — not after you have already fallen in love with a property and are rationalizing the cost. Here is how to integrate property tax estimation into your purchase decision framework intelligently.

Compare Tax Burdens Across Neighborhoods

Within a single metropolitan area, property tax rates can vary dramatically across municipal boundaries. A home in one suburb might carry a 1.2% effective tax rate while a comparable home three miles away in a different municipality carries a 2.1% effective rate — a $3,600 annual difference on a $400,000 home. This difference does not show up in the listing price, does not affect the mortgage payment, and is invisible in a basic affordability calculation — but it is completely real and permanent for as long as you own the property.

Run the Property Tax Estimator on every serious candidate property before making an offer. Compare effective tax rates, not just absolute dollar amounts — you want to know whether a given property's tax burden is high or low relative to its value, not just relative to other properties you are considering at different price points.

Calculate True Monthly Housing Cost

True monthly housing cost for a homeowner is mortgage principal and interest plus property taxes plus homeowner's insurance plus HOA fees plus average monthly maintenance. Property taxes are a fixed, unavoidable component of this calculation. A $2,200 per month mortgage payment on a home with $700 per month in property taxes represents a true housing cost of at least $3,200 per month before insurance and maintenance — 45% higher than the mortgage payment alone suggests.

Lenders calculate your debt-to-income ratio using PITI — principal, interest, taxes, and insurance — precisely because all four components are mandatory ownership costs. The Property Tax Estimator gives you the T in PITI so you can calculate your true monthly housing cost and verify that it fits within a prudent budget before committing to a purchase.

Property Taxes for Real Estate Investors

For real estate investors, accurate property tax estimation is an essential component of cap rate calculation and investment underwriting. Property taxes are one of the largest operating expenses for rental properties, and underestimating them produces inflated cap rates and investment returns that do not survive contact with reality.

Investors must be particularly careful about reassessment risk — the possibility that a property's assessed value will increase significantly after purchase, driving up operating costs and reducing net operating income below the underwritten projection. In full-assessment jurisdictions, buying a property that was last sold years ago at a much lower price guarantees a reassessment to the current purchase price, potentially doubling or tripling the tax bill from what the prior owner paid.

The Property Tax Estimator Calculator helps investors model post-purchase tax obligations accurately by defaulting to the purchase price as the assessed value base rather than using the current owner's potentially outdated assessment. This produces a conservative and realistic tax cost projection for underwriting purposes — which is exactly what sound investment analysis requires.

Frequently Asked Questions

How is property tax calculated on a home?

Property tax is calculated by multiplying your home's assessed value by the mill rate and dividing by 1,000. Assessed value is your home's market value multiplied by your jurisdiction's assessment ratio — which ranges from 10% to 100% depending on the state and county. The mill rate is the sum of tax rates levied by all jurisdictions with authority over your property — county, municipality, school district, and special districts. Any applicable exemptions (homestead, senior, veteran) reduce the assessed value before the mill rate is applied.

What is the average property tax rate in the United States?

The national average effective property tax rate — annual taxes divided by market value — is approximately 1.0% to 1.1% of home value. This average masks enormous variation: Hawaii averages around 0.28% while New Jersey averages around 2.2% to 2.5%. Your state, county, and municipality determine your actual rate far more than any national average. Always use location-specific data rather than national averages when estimating your property tax obligation.

Can my property taxes increase after I buy a home?

Yes — in most states, property taxes can and do increase after purchase. The primary drivers of increases are rising assessed values (from market appreciation or a reassessment cycle), increasing mill rates set by local governments and school districts, and expiration of exemptions. Some states limit assessment increases through caps — California's Proposition 13 limits annual increases to 2% for continuing owners, and Florida's Save Our Homes cap limits increases to 3% or the inflation rate, whichever is lower. Most states have no such cap, meaning assessments can rise as fast as market values.

What is a homestead exemption and how much does it save?

A homestead exemption reduces the assessed value of your primary residence for property tax purposes by a fixed dollar amount. Common homestead exemption amounts range from $10,000 to $100,000 depending on the state. The dollar savings depend on both the exemption amount and the local mill rate. A $50,000 homestead exemption in a jurisdiction with a 20 mill rate saves $1,000 annually. In most states, the homestead exemption must be applied for — it is not automatic — and filing deadlines apply in the first year of ownership.

How do I find out my property's assessed value?

Your property's current assessed value is a matter of public record and is available through your county assessor's office, either in person or through the assessor's online property search portal. Most counties now maintain searchable online databases where you can look up any property by address and see the assessed value, assessment history, tax bill amounts, and exemptions applied. Your annual tax bill or notice of assessment also states the assessed value. For pre-purchase estimates, use the purchase price as a proxy for assessed value in full-assessment jurisdictions.

Is it worth appealing my property tax assessment?

Appealing is worth pursuing whenever your assessed value appears to exceed your property's actual market value or exceeds the assessed values of comparable properties proportionally. Success rates for residential property tax appeals are meaningful — studies suggest 30% to 60% of appeals result in some assessment reduction. The cost of filing is low (often a modest administrative fee or free), the time investment for an informal hearing is a few hours of preparation, and a successful appeal reduces your tax bill permanently for as long as that assessment holds. The downside risk is essentially zero — the worst outcome is that your assessment stays the same.

How do property taxes affect my mortgage payment?

If your lender requires an escrow account — which most do for conventional loans with less than 20% down and for all FHA and VA loans — your monthly mortgage payment includes one-twelfth of your estimated annual property tax bill. A home with a $6,000 annual property tax obligation adds $500 to your monthly payment through escrow. When your property taxes increase, your escrow payment adjusts upward at the annual escrow analysis, increasing your total monthly payment even though your principal and interest payment remains unchanged. This is the most common reason a fixed-rate mortgage payment increases year over year.