What happens to your retirement plan if you live to 100?
Average life expectancy is the wrong number to plan to, because half of people exceed it by definition. What matters is the tail: the chance that you, or your spouse, are still spending at 95 or 100 — and the only assets that cover that outcome are the ones that keep paying however long you live.
- The distribution: average life expectancy is a midpoint, not a horizon.
- The couple effect: the relevant number is when the second of two people dies, which is later.
- What covers it: State Pension, defined benefit income and annuities keep paying regardless.
- What does not: a drawdown pot, which has a balance and can reach zero.
01 Why the average is the wrong number
Cohort life expectancy at 65 sits in the mid-eighties for both men and women in the UK, and a substantial minority live a decade beyond that. Planning to the average therefore means building a plan that fails roughly half the time, which is not a standard anyone would accept for anything else.
For a couple the relevant figure is later still. The plan has to fund the household until the second death, and the chance that at least one of two 65-year-olds reaches 95 is considerably higher than the chance for either individually.
That is what longevity risk means in practice: not that you will definitely live a long time, but that you cannot know, and the cost of being wrong is asymmetric. Running out of money at 94 is a far worse outcome than dying with money unspent.
Source: National life tables, UK
02 Which assets survive the tail
Three sources of income keep paying however long you live: the State Pension, a defined benefit pension, and an annuity. All three are inflation-linked or partly so, all three are backed by an institution rather than by a balance, and none of them can be exhausted.
A drawdown pot cannot make that promise. It has a balance, and a long life plus a poor sequence of returns is exactly the combination that empties it. That is not an argument against drawdown; it is an argument for not asking drawdown to cover the essential spending in year thirty-five.
The structure that follows is a floor and a top-up. Guaranteed income covers what you must spend; the portfolio covers what you would like to spend. At 95 the portfolio may be gone and the floor still arrives.
Source: The new State Pension
03 What the tail actually costs
Longevity's cost is compounded by inflation, because the years at the end are the ones furthest from today's prices. Thirty-five years at 3% inflation almost triples the cash needed to buy the same basket, so a level income that looked adequate at 65 buys a third of it at 100.
Care costs cluster in the same period, and with no cap in England the exposure is open-ended. A plan that survives to 100 on income alone can still be undone by four years of residential care in the nineties.
The practical response is not to save a much larger pot. It is to buy more guaranteed inflation-linked income — through State Pension deferral, through an annuity later in retirement, or by keeping housing equity available as the reserve of last resort.
Shows: how many years of income a portfolio supports at your withdrawal level, and what age that runs to. Ignores: investment returns, the State Pension, tax, and any change in spending as you age.
On the defaults above, the worked example shows age 91. The portfolio is exhausted around age 91, so the years beyond that are funded by guaranteed income alone.
Source: Inflation and price indices
Nobody plans to live to a hundred and roughly one in six women reaching 65 will see 95, which is close enough to matter. The mistake is treating life expectancy as a horizon when it is a midpoint — a plan built to it fails half the time by construction. What I would do instead is separate the two jobs. Guaranteed inflation-linked income covers the essentials for as long as you are here; the portfolio covers the discretionary spending and is allowed to run out. Then a very long life is an expensive surprise rather than a catastrophic one.
FAQ
How long should I plan for?
Longer than average life expectancy, which is a midpoint rather than a horizon. For a couple the relevant figure is the second death, and the chance that at least one of two 65-year-olds reaches 95 is considerably higher than for either alone.
What income keeps paying if I live that long?
The State Pension, a defined benefit pension and an annuity all continue regardless of how long you live, and all are inflation-linked or partly so. A drawdown pot has a balance and can be exhausted, which is why it should fund discretionary rather than essential spending.
Should I just save more?
A bigger pot helps and does not solve the problem, because a pot can still run out. Buying more guaranteed inflation-linked income — through State Pension deferral or an annuity later in retirement — addresses the tail directly rather than by making the balance larger.
Sources
Regulator references
- National life tables, UK · Office for National Statistics · 2023Cohort life expectancy at 65, which sets the planning horizon here.Last verified: 2026-09-07
- The new State Pension · GOV.UK · 2025Sets the qualifying-year rules and the full new State Pension rate this post works from.Last verified: 2026-09-07
- Inflation and price indices · Office for National Statistics · 2025The published index this post's real-terms figures are deflated by.Last verified: 2026-09-07
Calculator unit tests · the assertions this page's worked example is checked against, and their last result
Changelog
- 2026-09-07 — initial publish (new format)
Run this rule against your situation
See what this rule does to your own projection — month by month, to age 90.
Join the Waitlist
Jordan Reeves
Founder of Talk Through Wealth. A software engineer for over a decade before turning to retirement planning, Jordan built the projection engine after watching family members get fragmented, country-by-country advice that never reconciled. He writes about retirement the way the engine computes it: month-by-month, lifetime-long, and skeptical of any rule of thumb that hasn't been run through the math.