Would your retirement plan still work if you lived to 100?
Carol is a fictional retiree testing the same plan through ages 90, 95, and 100. Extending the endpoint does not predict her lifespan; it reveals how much margin the plan has for a longer retirement.
Written by James Wilson · Calculated and reviewed August 3, 2026
Starting assumptions
Carol is single, lives in Oregon, and retires at 64 with $650,000 Traditional, $80,000 Roth, $60,000 taxable, and $62,000 first-year spending that already includes healthcare. She claims $3,400 per month of Social Security at 67 in 2026 dollars and uses a Balanced portfolio, Lower Long-Term Returns, 2.5% inflation, the Simple Deterministic Medicare model, and no Roth conversions.
Same plan, three ending ages
| Result | Model / dollar basis | End at 90 | End at 95 | End at 100 |
|---|---|---|---|---|
| Success through ending age | 1,000 simulated futures | 86.3% | 79.3% | 73.4% |
| Ending balance | Smooth deterministic projection; inflation-adjusted | $522,674 | $472,391 | $410,594 |
| Cumulative estimated taxes | Annual future-dollar amounts | $223,519 | $288,479 | $365,551 |
| Informational Medicare/health estimate already included within planned spending | Annual future-dollar amounts | $89,873 | $114,801 | $143,005 |
| Success through age 80 | 1,000 simulated futures | 99.3% | 99.3% | 99.3% |
The age-80 result stays identical because nothing before 80 changed. The ending-age success rate falls as five and then ten additional years of spending, inflation, taxes, withdrawals, and market exposure are added. Because healthcare is included in planned spending, the informational Medicare/health estimate is not added to spending a second time.
What Carol could test
- Use a longer ending age as a stress test.
- Separate essential and flexible later-life spending.
- Review survivor income and filing-status changes for couples.
- Test higher healthcare costs and inflation.
- Compare guaranteed income and portfolio withdrawals over the extended years.
Recreate the study
- Load the study, which begins with Ending Age 100 and the 67 · No Roth scenario.
- Run Retirement Risk Analysis and record success through ages 80 and 100.
- Change only Ending Age to 95, rerun the analysis, and record the result.
- Repeat with Ending Age 90 to compare all three longevity stress tests.
Engine support through age 100
This study uses IRS Publication 590-B Table III (Uniform Lifetime) denominators through age 100. Table III generally applies to IRA owners unless a spouse who is more than 10 years younger is the sole beneficiary; different tables and rules can apply in other circumstances. Actual RMD treatment depends on current law and individual circumstances.
Stress-test a longer life
Change only the Ending Age and compare the same strategy through 90, 95, and 100.
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