Ideal Weight Calculator - Find Your Healthy Weight Range by Height and Frame

"What should I weigh?" is one of the most commonly searched health questions, and one of the most commonly misunderstood. There is no single perfect number for any given height - there is a reasonable range, shaped by frame size, muscle mass, and individual body type. What there is, however, is decades of clinical reference formulas that give a useful starting estimate.

This guide explains where the classic ideal weight formulas come from, how they compare to each other, walks through real worked examples, and shows you how to use the ideal weight health calculator wellness metrics tool at CalcAdvisor.com as one input among several for thinking about a healthy target weight.

What "Ideal Weight" Actually Means - and Why No Single Number Fits Everyone

The term "ideal body weight" originated in clinical medicine, primarily to help estimate medication dosing and assess nutritional status in hospital settings - not as a beauty or fitness standard. The formulas were built from population averages decades ago and produce a single number based only on height and sex, with a frame-size adjustment as the only nod to individual variation.

In modern practice, body fat percentage and waist-to-height ratio are generally considered more informative individual health metrics than a height-based ideal weight number, because they account for body composition rather than total mass alone. Still, ideal weight formulas remain a useful, simple starting reference point - especially when paired with these more detailed metrics rather than used alone.

Devine, Robinson, and Hamwi - Comparing the Classic Formulas

Three formulas dominate this space, all developed for clinical dosing purposes between the 1960s and 1980s. The Devine formula (1974), originally created for drug dosage calculations, is the most widely used today: Men: 50kg + 2.3kg per inch over 5 feet. Women: 45.5kg + 2.3kg per inch over 5 feet. The Hamwi formula (1964) uses nearly identical logic with slightly different constants. The Robinson formula (1983) is a refinement of Devine with marginally adjusted constants based on updated population data.

All three produce results within a few kilograms of each other for most heights, and all share the same fundamental limitation: they were built from general population data decades ago and do not account for an individual's actual muscle mass, frame size beyond a single adjustment factor, or body composition.

The Formula Explained With a Full Worked Example

Devine Formula - Men: Ideal Weight = 50kg + 2.3kg x (height in inches - 60)

Devine Formula - Women: Ideal Weight = 45.5kg + 2.3kg x (height in inches - 60)

Worked example - Andrew, male, 5'10" (70 inches): Ideal Weight = 50 + 2.3 x (70 - 60) = 50 + 2.3 x 10 = 50 + 23 = 73kg. Andrew's baseline Devine ideal weight is 73kg, before any frame-size adjustment.

Frame size adjustment: Small frame: subtract 10%. Medium frame: no adjustment. Large frame: add 10%. For Andrew with a large frame: 73kg x 1.10 = 80.3kg. With a small frame: 73kg x 0.90 = 65.7kg. This is why the calculator presents a range, not one rigid number.

Worked example - Sofia, female, 5'4" (64 inches): Ideal Weight = 45.5 + 2.3 x (64 - 60) = 45.5 + 2.3 x 4 = 45.5 + 9.2 = 54.7kg. With a medium frame, Sofia's reference range is approximately 49-60kg accounting for the typical clinical tolerance built into these formulas.

How to Use This Calculator on CalcAdvisor.com

Step 1 - Enter your height and sex. These drive the core Devine formula calculation.

Step 2 - Select your frame size. If unsure, wrap your thumb and middle finger around your wrist - if they overlap easily, you likely have a small frame; if they just touch, medium; if there's a gap, large.

Step 3 - Review your ideal weight range. The result shows a range, not a single rigid target, reflecting the genuine uncertainty in any height-only formula.

Step 4 - Cross-reference with BMI and body fat percentage. For a much more complete picture, pair this result with the BMI Calculator and Body Fat Calculator also available at CalcAdvisor.com.

Calculate your ideal weight range now at https://www.calcadvisor.com/calculators/ideal-weight-calculator.

3 Real-World Examples

Example 1: Rachel, 5'5", Medium Frame, Using This as a General Check-In

Rachel is 65 inches tall. Ideal Weight = 45.5 + 2.3 x (65-60) = 45.5 + 11.5 = 57kg. At her current weight of 59kg, Rachel sits comfortably within the typical clinical range for her height, confirming there's no urgent reason for concern based on this metric alone.

Example 2: Tom, 6'2", Large Frame, Former College Athlete

Tom is 74 inches tall. Base Devine: 50 + 2.3 x (74-60) = 50 + 32.2 = 82.2kg. With a large frame adjustment: 82.2 x 1.10 = 90.4kg. Tom currently weighs 95kg with significant muscle mass from years of strength training. Despite being slightly above the formula's adjusted range, his body fat percentage (measured separately at 16%) is well within healthy limits - illustrating exactly why this formula shouldn't be the only metric used for someone with above-average muscle mass.

Example 3: Priya, 5'1", Small Frame, Setting a Realistic Post-Pregnancy Goal

Priya is 61 inches tall. Base Devine: 45.5 + 2.3 x (61-60) = 45.5 + 2.3 = 47.8kg. With a small frame adjustment: 47.8 x 0.90 = 43.0kg. Priya's doctor advised her that this lower end of the formula's range is likely too aggressive a target so soon after pregnancy, and recommended using it as a long-term directional reference rather than a near-term goal, alongside gradual, sustainable nutrition changes.

Common Mistakes to Avoid

• Treating the result as a precise target rather than a rough range: These formulas have a built-in clinical tolerance of several kilograms in either direction; chasing the exact center number is not necessary or particularly meaningful.
• Ignoring frame size and bone structure entirely: Skipping the frame adjustment produces a less personalized, less useful estimate, especially for people at either end of the frame-size spectrum.
• Applying adult formulas to teenagers or children: These formulas were validated on adult populations; growing children and teens need pediatric growth charts instead.
• Using this as the sole metric for athletes or heavily muscled individuals: As shown in Tom's example, significant muscle mass can put someone above the formula's range while still being perfectly healthy.
• Comparing your number directly to someone of a different height: The formula's height adjustment is linear and specific - there's no useful shortcut comparison between people of different heights.
• Using it during pregnancy or shortly postpartum as a strict target: These formulas were not designed for these physiological states; follow guidance from an obstetrician instead.
• Forgetting these formulas predate modern body composition science: They are useful historical reference points, not the most scientifically current way to assess healthy weight for an individual today.

Expert Tips

• Use this as one data point among several, not a standalone verdict. Pair it with BMI and, ideally, body fat percentage for a fuller picture.
• Focus on the range, not a single number. The small-to-large frame range typically spans 10-15kg - that's the realistic zone, not one exact figure.
• Recheck your frame size honestly. The wrist-circumference method is simple and reasonably reliable for most adults.
• Don't use this formula alone to judge athletes or bodybuilders. Muscle mass will consistently push these individuals above the range without any health concern.
• Discuss any significant weight goal with a doctor or registered dietitian. Especially if your current weight differs substantially from the calculated range, professional guidance accounts for factors a formula cannot.

Frequently Asked Questions

Which ideal weight formula is most accurate - Devine, Robinson, or Hamwi?

All three formulas produce results within a few kilograms of each other for most heights, since they were developed using similar population data and methodology between the 1960s and 1980s. The Devine formula is the most widely used today, particularly in clinical medication dosing contexts, which is why it's the standard formula used in most modern ideal weight calculators.

Is ideal weight the same as a healthy weight?

Not exactly. Ideal weight formulas were originally developed for clinical purposes like medication dosing, using only height and sex as inputs. A genuinely healthy weight for an individual depends on additional factors like body composition, muscle mass, age, and overall metabolic health, which is why these formulas should be treated as a rough starting reference rather than a complete health assessment.

Why does my ideal weight range seem too low or too high for me?

If you have significantly more or less muscle mass than the average population the formula was built from, your result will likely feel off. Athletes and heavily muscled individuals commonly fall above their calculated range while remaining perfectly healthy, since these formulas cannot distinguish muscle mass from fat mass the way a body fat percentage measurement can.

How do I determine my frame size accurately?

A common simple method is to wrap your thumb and middle finger around your opposite wrist at its narrowest point. If your fingers overlap, you likely have a small frame. If they just touch, medium frame. If there's a visible gap, large frame. This isn't a precise clinical measurement, but it's a reasonable practical estimate for adjusting the ideal weight formula.

Should I use this calculator to set a weight loss goal?

It can serve as one general reference point, but it shouldn't be your only guide for setting a weight loss goal. Body fat percentage, waist-to-height ratio, and how you feel functionally and physically are generally more informative for setting an individual target. Discussing specific goals with a doctor or registered dietitian is recommended, especially for significant weight changes.

Do these formulas work the same way for older adults?

The formulas don't explicitly adjust for age beyond the original population data they were built from. Some research suggests slightly higher weight ranges may be associated with better health outcomes in older adults (sometimes called the "obesity paradox" in geriatric literature), which is a nuance these decades-old formulas don't capture. Older adults should weigh this calculator's output alongside guidance from their physician.

Final Thoughts

An ideal weight formula gives you a useful, fast starting reference point - but it was never meant to be the final word on what your body should weigh. Use it alongside body fat percentage, waist-to-height ratio, and how you actually feel and function, rather than as a strict target to chase.

Find your ideal weight range now at https://www.calcadvisor.com/calculators/ideal-weight-calculator, and consider pairing the result with the Body Fat Calculator at CalcAdvisor.com for a more complete picture of your body composition and health.