How Long Will My Pension Need to Last?

Why does retirement length matter so much?

Imagine two people each retire with exactly the same pension.

One retires at 68. The other retires at 58.

Even if they have identical lifestyles, the second person could potentially need another ten years of income. That's:

• ten more years of household expenditure;
• ten fewer years of earnings;
• potentially ten fewer years of pension contributions;
• less time for investments to grow before withdrawals begin;
• and possibly a longer period before State Pension starts.

So retirement age doesn't just affect when you stop working. It affects how long your money may need to support you.

Steve's observation

We spend years asking: "When can I retire?" But there's another question hiding behind it: "If I retire then, how long might I need to pay myself for?"

That's where retirement planning gets slightly awkward. Your employer knew when payday was. Your pension doesn't know when your final payday will be.

So you have to build a plan without knowing exactly how many paydays retirement will contain.

Life expectancy is a starting point, not an expiry date

The Office for National Statistics provides life-expectancy information that can help give you a starting point.

Current UK national life-table figures show that, at age 65, average remaining life expectancy is around 18.7 years for men and 21.2 years for women.

That would take the average 65-year-old to roughly their mid-80s.

But averages can be misleading when used for individual retirement planning. Some people will die younger. Others will live far longer.

And the ONS also provides cohort life-expectancy projections, which take expected future mortality improvements into account.

So don't look at an average figure and conclude: "Excellent. I only need the money to last until 84." That's not what the statistic means.

Why planning to the average can go badly wrong

Imagine average life expectancy suggests somebody might live into their mid-80s. They build a retirement plan designed to exhaust their money at 85. Then they reach 85. Healthy. Active. And very much still requiring food, heating and somewhere to live.

The problem with an average is simple: roughly half of people will be on one side of it and half on the other.

Retirement planning therefore needs to allow for the possibility of living materially longer than average.

What does MoneyHelper suggest?

MoneyHelper makes a useful point: people often underestimate how long retirement could last, so it can make sense to plan for several years longer than you expect.

Their example is straightforward. If someone retires at 68 and thinks they may live until 90, that's around 22 years of retirement. MoneyHelper suggests considering a plan that lasts at least 25 years.

The point isn't that everybody should automatically plan for exactly 25 years. It's that adding a margin for longevity can make a retirement plan more resilient.

Your retirement age changes everything

Let's compare a few simple examples.

That's why "I've got £400,000. Is that enough?" is incomplete.

£400,000 supporting 20 years is a very different proposition from £400,000 potentially supporting 35 years.

If you're trying to judge whether a pension pot is enough, start with ODW-RP-004 — Is £100,000, £250,000 or £500,000 Enough to Retire?

Don't confuse pension-access age with retirement duration

Private pensions can usually currently be accessed from age 55, with the normal minimum pension age scheduled to rise to 57 from April 2028, subject to protections and exceptions.

That doesn't mean: "Your pension is designed to last from age 55." It simply tells you when access may become available.

The earlier you begin taking money from a pension, the longer that money may potentially need to support you.

We've covered access separately in ODW-WP-015 — When Can I Take Money From My Workplace Pension?

Being able to access the pension is not the same as it being sensible to start spending it.

State Pension changes the job your private pension has to do

Imagine you retire at 60. For the first part of retirement, your private pensions, savings and investments may need to fund most of your lifestyle. Later, State Pension begins. That introduces another regular source of income.

So your private pension doesn't necessarily need to provide the same amount every year. For example:

That's why retirement needs to be viewed as a timeline. If you haven't built yours yet, see ODW-RP-007 — How Do I Work Out My Total Retirement Income?

Retirement isn't one 30-year block

Spending may also change. Your first decade might involve:

• travelling;
• holidays;
• hobbies;
• eating out;
• helping family;
• home improvements.

Later retirement could look different. Some discretionary spending might reduce. Other expenditure could emerge.

So planning for 30 years doesn't necessarily mean assuming identical spending for every one of those 30 years.

The important point is that the financial resources remain capable of supporting the different stages.

Couples have a bigger longevity problem

If you are planning retirement as a couple, the financial plan doesn't only need to consider: how long will I live? It needs to consider: how long might either of us live?

Even if each person's individual probability of living to an advanced age appears modest, the chance that at least one partner survives for a long time can be materially greater.

That means a couple's retirement assets may need to support the household until the second death, not the first.

What happens to income after one partner dies?

Some retirement income may continue. Some may reduce. Some might stop. For example, the survivor's:

• State Pension position may differ;
• defined benefit survivor benefits depend on scheme rules;
• pension assets may pass under applicable rules;
• household tax position may change.

Meanwhile, expenditure doesn't simply halve. There is still:

• council tax;
• heating;
• insurance;
• maintenance;
• transport;
• food;
• and general living costs.

That's why retirement longevity planning should include a survivor scenario.

Should I plan to age 100?

There isn't one age everybody should automatically use. Planning assumptions should reflect:

• current age;
• health;
• family longevity;
• lifestyle;
• retirement age;
• household situation;
• secure income;
• other assets;
• attitude to risk.

But modelling an advanced age can be useful. You don't have to believe you will live to 100 to ask: "What happens financially if I do?" It's a stress test, not a prediction.

What about poor health?

Someone in poor health may reasonably think their life expectancy could be shorter than statistical averages. That can be relevant.

But estimating individual longevity is difficult. Some medical conditions materially reduce life expectancy. Others don't develop as expected.

Retirement decisions can also be irreversible. So health can be part of the planning assumptions, but it shouldn't be treated casually as certainty.

Family history matters — but don't over-rely on it

People sometimes say: "Nobody in my family has made it past 80, so I'm not planning beyond that."

Family history can be relevant. But your parents and grandparents lived in different periods. But your parents and grandparents lived in different periods with different:

• healthcare;
• treatments;
• working conditions;
• smoking patterns;
• diets;
• lifestyles.

You aren't necessarily going to repeat their lifespan. Likewise, having long-lived parents doesn't guarantee you'll reach 100.

Use family history as context — not an expiry date.

What happens if I underestimate longevity?

This is the central risk. If you plan for 20 years and retirement lasts 30, the final ten years still need funding. That could mean:

• lower spending;
• reduced financial flexibility;
• reliance on guaranteed income;
• using other assets;
• downsizing;
• or potentially financial hardship.

And unfortunately, those problems arrive later in life when returning to full-time work may be considerably less realistic.

That's why longevity risk deserves attention before retirement.

What happens if I overestimate longevity?

There is another side. If you plan so cautiously that you're terrified to spend anything, you could reach later retirement with significant unused assets but have unnecessarily restricted the years when you were healthiest and most able to enjoy them.

So retirement planning isn't about: "Spend as little as possible so you never run out." It's about balancing enjoying retirement today with protecting tomorrow.

That's a much more difficult — and much more useful — objective.

Steve's observation

There are two ways a retirement plan can fail.

The obvious one is: you run out of money before you run out of life.

But there's another. You spend 30 years frightened to touch the money, then discover you could have afforded the holidays, experiences and memories you kept saying no to.

A good retirement plan should try to protect against both.

Guaranteed income can reduce longevity risk

Some retirement income continues for life. Examples can include:

• State Pension;
• defined benefit pension income;
• annuity income, depending on its terms.

That can be valuable because those income streams aren't exhausted simply because somebody lives longer than expected.

By contrast, money held in investment portfolios and defined contribution pensions depends on withdrawals, investment performance, charges, inflation and how long the money remains invested.

Understanding the split between lifetime income and finite assets is therefore important.

Inflation makes a long retirement harder to plan

Imagine retirement lasts 30 years. Even modest inflation over that period can materially change the cost of living.

So the question isn't simply: "Will £30,000 a year last for 30 years?" It's: "Will my income and assets continue providing the spending power I need throughout those 30 years?"

Some income may increase with inflation. Some may increase differently. Some may remain level. And investment returns are uncertain.

Longevity and inflation therefore interact.

Investment risk matters more because retirement can be long

Retiring doesn't necessarily mean investment ends. Some pension money may remain invested for decades. That means growth can still be important. But markets can also fall.

The challenge is balancing the need for money to potentially grow against the need to fund withdrawals and manage investment risk.

That balance can change throughout retirement.

Don't plan only for the first five years

It's completely natural to focus on the retirement you can see. The first holiday. The first year without work. The mortgage ending. The new car.

But retirement planning needs to look further. Ask: what does age 75 look like? Age 85? Age 95?

Not because we can predict those years precisely. Because ignoring them doesn't make them disappear.

The three numbers I'd write down

Start with the age you want to retire. Then choose a central longevity assumption. And finally a longer-life stress-test age.

For example, someone might model: retirement at 60, central plan to age 90, stress test to age 95 or 100.

Those are illustrations, not recommendations. What matters is testing whether an unexpectedly long life creates a financial problem.

What Should I Do Next?

Take your proposed retirement age. Then ask: how many years to age 85? How many to 90? How many to 95? What happens at 100?

Now put your retirement-income timeline beside those ages. Where does:

• State Pension begin?
• guaranteed pension income start?
• mortgage expenditure stop?
• private pension withdrawals reduce?
• one partner potentially become financially dependent on survivor income?

You're not trying to predict your date of death. You're checking whether a long life would create a financial problem.