Planning age

How long should a retirement plan last? Choosing your planning age

By Lei Huang · October 6, 2026 · Last updated October 6, 2026 · 9 min read

One setting on Runway's Basics step quietly drives every result: the Plan through age. It's the age your money has to last to. Pick too low and you may run out while you're still alive; pick too high and you spend less than you could. This guide gives the odds of living to various ages from the Social Security Administration, shows what each planning age does to a plan in Runway's engine, and offers a way to choose.

Quick answer. Plan past life expectancy, because it's only the middle of the range. SSA's 2023 period life table puts a 65-year-old's chance of reaching 90 at 24.1% for a man and 34.9% for a woman, of reaching 95 at 8.0% and 14.4%, and of reaching 100 at 1.3% and 3.2%. For a man and a woman both 65, the chance that at least one is alive is 50.6% at 90, 21.3% at 95 and 4.4% at 100 (assuming their lifespans are independent). For the sample couple spending $110,000, the chance the money lasts is 92.5% if you plan through 90, 84.9% through 95, 75.8% through 100 and 70.1% through 105. At a 90% target, each extra five years of planning cuts sustainable spending by about $5,700 a year, or about 5%. Runway's default is 95, a common cautious choice.

Why plan past life expectancy?

Life expectancy is an average. SSA's 2023 period life table (the one used in the 2026 Trustees Report) gives a remaining life expectancy at 65 of 18.12 years for men and 20.66 for women, which puts the average at about 83 and 86. But half of people live longer than the middle, and a retirement plan has to work for the person who does. The table also gives, for each age, how many of 100,000 people born alive are still living, which lets you work out the odds of reaching any age from 65:

Chance of being alive at…	Man, 65 today	Woman, 65 today	At least one of a man and woman, both 65	Both
80	64.2%	73.9%	90.7%	47.5%
85	44.9%	56.6%	76.1%	25.4%
90	24.1%	34.9%	50.6%	8.4%
95	8.0%	14.4%	21.3%	1.2%
100	1.3%	3.2%	4.4%	0.0%

For a couple, what matters is whether either of you is still alive and spending, so the "at least one" column is the one that tells you how long the plan is really needed. About 1 couple in 5 has someone alive at 95.

Three cautions. The couple figures assume the two lifespans are independent, which understates how often both die close together. The table describes the whole Social Security population, not your health or family history; SSA's own life expectancy calculator says its estimate is "based only on the sex and date of birth you enter." And a period table applies 2023's death rates to every future year, so it can't anticipate later improvements or setbacks.

What does Plan through age do in Runway?

It sets how many years the simulation runs. Runway tests whether your spending target is met every year until the first person listed reaches that age, so if you set 95 and the first person is a year older than the second, the plan ends when the second is 94. The longer the horizon, the more years of withdrawals and the more chances for a bad market stretch. Here is the sample couple (Pat 65, Alex 64, $1.46 million) at two spending levels, with only the planning age changed:

Plan through	Lasts at $95,000	Median ending at $95,000	Lasts at $110,000
85	99.9%	$1,633,420	98.3%
90	99.7%	$1,594,463	92.5%
95 (default)	99.4%	$1,483,604	84.9%
100	97.2%	$1,347,196	75.8%
105	95.2%	$1,213,794	70.1%

At comfortable spending, the planning age barely matters: going from 95 to 100 costs 2.2 points. Near the edge it matters a lot: at $110,000 the same step costs 9.1 points, and the step after it costs about 6 more.

What does a longer plan cost in spending?

The same trade-off in dollars: the most this couple could spend each year and still have a 90% chance the money lasts, with only the planning age changed (the search is accurate to a few hundred dollars):

Plan through	Spending with a 90% chance of lasting	Compared with planning to 95
90	$112,637	+5.3%
95	$106,934	none
100	$101,230	−5.3%

Each extra five years of planning costs about $5,700 a year, roughly 5% of spending. That is the price of insurance against a long life: modest and visible, set against the chance of running out at 90 or later, when there is little room to adjust.

So what age should I choose?

Start at 95. It's Runway's default and, for a couple, it covers the ages at which about 1 in 5 couples still has someone alive. Choose 100 if you want a wider margin or have a family history of long lives; 90 is a bet that you'll be in the first half.
Think about the survivor. The plan stops at the first listed person's age, so if that person is older, the younger spouse's last planned year is earlier than the number you typed. A couple with a large age gap may want to add a few years.
Look at when a plan fails, not only whether. A plan that first runs short at 92 is a different problem from one that runs short at 80 (how to read the results).
Keep flexibility in reserve. If you could cut spending 10% in a bad stretch (see guardrails), a longer horizon is less costly to carry.
Revisit it. Your health, your family's longevity and your savings change. The planning age is a setting, not a verdict; check it when you update your plan each year.

Test your own planning age. Change Plan through age on the Basics step, recalculate, and see how the chance your money lasts moves.

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What does this leave out?

Individual health and wealth. The SSA table covers everyone. Your own odds may be better or worse.
One spouse dying earlier. The couple odds treat the two lives as independent, and the engine runs the plan to a single age rather than modeling each spouse's death.
Falling spending. Many people spend less late in life, which a flat spending target doesn't capture, though healthcare and long-term care can push the other way (see long-term care).
Social Security timing. Claiming-age decisions have their own break-even ages (see the claiming guide).

How were these numbers computed?

The odds of reaching each age come from the Social Security Administration's Actuarial Life Table, the 2023 period life table for the Social Security area population used in the 2026 Trustees Report (read on October 6, 2026). The chance of being alive at a given age is the table's number of survivors at that age divided by the number at 65, for men and for women separately; the couple figures combine them assuming independent lifespans. The planning-age results are Runway's engine on the sample couple: married filing jointly, Social Security claimed at 69 and 68, 60% stocks and 40% bonds with stocks at 7.5% and bonds at 2.93% a year after inflation and volatilities of 16% and 6%, long-term-care costs left out, 2,000 simulated markets with seed 2026. The 90% spending figures use Runway's sustainable-spending search on the same household. All amounts are in today's dollars.

Runway content is educational only and is not financial, tax, or legal advice. Consult a qualified professional before making financial decisions.

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About the author

Lei Huang is a former professor, turned founder and developer. He builds Runway, a DIY retirement income planner whose planning engine computes the figures in these posts. He is not a financial advisor.