How Much Do You Need to Retire?

A widely used starting point is to multiply your expected annual retirement spending by about 25, which corresponds to withdrawing roughly 4% of your pot each year. So if you expect to spend a given amount annually, you aim for a pot around 25 times that figure. Your real number depends on spending, other income, life expectancy and how conservative you want to be. It is one of the most important numbers you will ever estimate, and most people never try.

The question feels impossibly large until you break it down. You do not need to predict the future perfectly. You need a sensible first estimate, built from your own spending, that you refine as the years pass. This guide shows you how to build that estimate.

Where this fits: this is the destination that long-term investing is aiming at. The pot is built using the habits in automating your finances and grown through the compounding described in the stock market: why a long time horizon is your biggest advantage. The withdrawal logic behind the number is explained fully in the 4% rule for retirement explained.

Start With Spending, Not a Round Number

The most common mistake is to pick a large round number and aim for it because it sounds impressive. That is backwards. The right starting point is not how much you want to have; it is how much you expect to spend.

Your retirement pot exists for one purpose: to fund your living costs once you stop earning. So the whole calculation begins with a single question: how much will you spend in a typical year in retirement?

Estimate this honestly. Think in terms of today’s money, covering housing, food, utilities, transport, healthcare, leisure and the occasional larger cost. Many people find their retirement spending is somewhat lower than their working-life spending, because commuting costs, mortgage payments and the cost of raising children often fall away. Others want to travel more and spend as much or more. Your figure is personal.

The 25x Rule: A Simple First Estimate

Once you have an annual spending figure, a widely used shortcut converts it into a target pot:

Target pot ≈ annual retirement spending × 25.

So if you expect to spend a certain amount each year, you aim to accumulate roughly 25 times that amount in invested assets. The logic is that a pot of that size should, under historical conditions, allow you to withdraw about 4% in the first year and adjust for inflation thereafter, without running out over a long retirement. This is the retirement side of the 4% rule, and the 25x multiple is simply its reciprocal: withdrawing 4% a year is the same as needing 25 times your spending.

The rule’s appeal is that it ties your target directly to your lifestyle rather than to an arbitrary number. Spend less, and your target falls. This is one more reason that resisting lifestyle inflation is so powerful: every pound you can comfortably live without in retirement reduces the pot you need by about 25 pounds.

Hypothetical illustration: imagine two people. Person A expects to spend a certain amount each year and keeps their lifestyle modest. Person B expects to spend twice as much. Under the 25x rule, Person B needs a pot twice as large as Person A, and must save far more or work far longer to reach it. Their investment returns might be identical; the difference is entirely in their chosen spending.

Subtract Your Other Income First

The 25x rule applies only to the spending your own investments must cover. Before you multiply, subtract any reliable income you will receive in retirement from other sources.

Common sources include:

• A state pension or equivalent. Many countries provide a baseline retirement income. This reduces the amount your pot must generate.
• A defined-benefit (final salary) pension. If you are fortunate enough to have one, it provides guaranteed income that directly lowers your target.
• Other income, such as rental income or an annuity you intend to buy.

The method is straightforward:

1. Estimate your total annual spending in retirement.
2. Subtract the annual income you expect from other reliable sources.
3. The remainder is the “gap” your investment pot must fund.
4. Multiply that gap, not your total spending, by 25.

This step matters enormously, because guaranteed income is extremely valuable. A solid state or workplace pension can cut the pot you need to build yourself by a large margin.

Step	What you do	Example label
1	Estimate annual retirement spending	Total spending need
2	Subtract reliable pension and other income	Guaranteed income
3	Find the shortfall your pot must cover	The gap
4	Multiply the gap by about 25	Target pot

Factors That Change Your Number

The 25x estimate is a starting point. Several factors push your real target up or down.

How long your retirement lasts

The 4% logic was studied mainly around retirements of roughly 30 years. If you plan to retire unusually early, your money must last much longer, which argues for a larger pot or a more cautious withdrawal rate. If you retire later, the pot has to last fewer years.

Your tolerance for risk and uncertainty

The 25x rule rests on assumptions about investment returns and inflation that may not hold in future. If you want a larger safety margin, aim beyond 25 times, say 28 or 30 times your spending. The investing principle of a margin of safety applies to retirement planning too: building in a cushion protects you when reality turns out worse than your assumptions.

Taxes

Depending on your country and the type of account, withdrawals in retirement may be taxed. The 25x rule works best when applied to your genuine after-tax spending need, so be realistic about the difference between what you withdraw and what you can actually spend.

Inflation

Prices rise over time, so the amount you need will grow in nominal terms across a long retirement. Estimating in today’s money and keeping a portion of your pot invested for growth, rather than entirely in cash, both help your money keep pace.

Big one-off costs and legacy wishes

If you expect large one-off costs, such as supporting family or significant healthcare, or if you want to leave money behind, add those on top of the basic 25x figure.

Putting a Number On It

With your inputs in hand, the arithmetic is simple, and you do not have to do it by hand. The retirement calculator lets you test how different spending levels, timelines and contributions affect the pot you need and whether you are on track to reach it. The FIRE calculator is useful if you are aiming for early financial independence, where the longer horizon changes the maths. And once you have a target pot, the withdrawal rate calculator helps you see how long that money might last at different rates of spending.

Use these tools to turn the estimate into a plan: a target pot, a monthly contribution, and a timeline. Then let compounding and consistency do the rest over the years.

Treat the Number as a Living Estimate

Finally, hold your retirement number lightly. It is a first draft, not a verdict. Your spending will change, your income sources will become clearer, markets will do what they do, and your plans will evolve. Revisit the estimate every few years, especially as retirement approaches and the guesswork shrinks.

What matters far more than pinpoint accuracy is starting early and contributing consistently. A rough target that you act on today will serve you far better than a perfect target you calculate but never fund.

Frequently Asked Questions

What is the 25x rule for retirement?

It is a shortcut that says you need roughly 25 times your annual retirement spending invested. It is the mirror image of the 4% rule, since withdrawing 4% a year is the same as having 25 times your spending. It gives a quick first estimate, not a guarantee.

Does my state or workplace pension reduce how much I need?

Yes, significantly. Any reliable income you will receive in retirement reduces the amount your own investments must cover. You apply the 25x rule only to the spending that your pot needs to fund, after other income is counted.

Should I use gross or net spending to estimate my retirement number?

Use the amount you actually expect to spend each year in retirement, remembering that withdrawals may be taxed depending on the account and your country. Estimating your real after-tax spending need gives the most honest target.

How accurate is the 25x estimate?

It is a useful starting point, not a precise answer. It rests on assumptions about returns, inflation and how long you live. Treat it as a first draft that you refine as your retirement approaches and your circumstances become clearer.

Your Next Step

Your retirement number is only useful once it becomes a plan you fund every month.

• Estimate your target and track your progress with the retirement calculator and, for early retirement, the FIRE calculator.
• Understand the withdrawal logic behind the number in the 4% rule for retirement explained.
• Make funding the pot effortless by automating your finances and beating lifestyle inflation.

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About the author: Cameron Hayes is a senior investor relations and finance professional who has worked in IR at Nasdaq Copenhagen-listed companies including Nilfisk and Maersk Drilling. He holds an MSc from Copenhagen Business School and a BCom from the University of Ottawa, and founded Gingernomics to teach individual investors the Five Criteria framework. More about Gingernomics.

The content on Gingernomics is for educational and informational purposes only and does not constitute financial advice. Always do your own research and consult a licensed financial advisor before making any investment decisions. Past performance is not indicative of future results.