Longevity Planning Calculator - How Much Do You Need to Retire at 90 or 100?
A healthy 65-year-old woman today has approximately a 50 percent chance of living past 87. A married couple at 65 has a 50 percent chance that at least one spouse survives past 92. The longevity planning calculator how much to retire at 90 or 100 calculates the retirement corpus needed to fund your annual spending, inflation-adjusted, through any target age.
The Formula Explained
Corpus = W x [1 - ((1+g)/(1+r))^n] / (r - g). Where W = first year withdrawal; r = portfolio return rate; g = inflation rate; n = years in retirement.
Worked example 1 (retire at 65, target age 90, 25 years): Linda needs $50,000/year, 6 percent return, 3 percent inflation. Corpus: $50,000 x 16.374 = $818,700.
Worked example 2 (same, target age 100, 35 years): Corpus: $50,000 x 21.225 = $1,061,250. Only $242,550 more for 10 additional years of security.
| Target Age | Planning Horizon | Corpus Needed ($50k/yr, 6%, 3% inflation) |
|---|---|---|
| Age 85 | 20 years | $726,000 |
| Age 90 | 25 years | $819,000 |
| Age 95 | 30 years | $884,000 |
| Age 100 | 35 years | $1,061,000 |
How to Use This Calculator on CalcAdvisor.com
Access the full calculator at https://www.calcadvisor.com/calculators/longevity-planning-calculator.
3 Real-World Examples
Example 1: Helen, 62, Planning for Potential Supercentenarian Life
Helen's mother is 94, grandmother lived to 101. Needs $48,000/year. Corpus at 90: $786,000; at 95: $876,000; at 100: $1,019,000. She targets $1,019,000 and finds a $47,000 gap from her projected $972,017 - closes it by working 6 more months.
Example 2: Arthur and Ruth, 67 and 65, Modeling Survivor Longevity
They need $52,000/year together and $38,000/year for the survivor. They need approximately $900,000 to $950,000 at retirement to fund both joint and survivor phases with high confidence to the 90th percentile.
Example 3: James, 55, Super Longevity Plan for a 45-Year Retirement
Plans to retire at 60. Needs $62,000/year. 45-year retirement (to age 105). Corpus needed: $62,000 x 22.251 = $1,379,562. He has a $315,000 gap - bridges it by increasing contributions and accepting part-time income for the first 10 years of retirement.
Common Mistakes to Avoid
- Planning only to average life expectancy.
- Using nominal withdrawal amounts without inflation adjustment.
- Underestimating healthcare cost inflation specifically.
- Ignoring the long-term care wildcard.
- Treating the corpus as a hard target rather than a planning floor.
- Not revisiting the longevity plan as healthcare and genetics evolve.
- Conflating portfolio corpus with guaranteed income when assessing longevity coverage.
Final Thoughts
Find your specific corpus requirement for any target age at https://www.calcadvisor.com/calculators/longevity-planning-calculator.