How much do you need to retire early? A realistic calculation for UK, EU, and US savers

Most of the retirement calculators on the internet will tell you the same thing. Save 25 times your annual spending, withdraw 4% a year, you are set for 30 years. This advice is so common it has become something close to a catechism in financial independence circles. It is also, for most of the people reading it, wrong.

Not wrong because the arithmetic is broken. Wrong because it was built on US market data between 1926 and 1995, assumes a 30-year retirement, does not distinguish between tax wrappers, and does not care which country you live in. If you are a 45-year-old in Manchester planning to retire at 55, a 38-year-old in Munich eyeing 50, or a 42-year-old in Austin targeting the same, you are each looking at a different calculation. Applying the same number to all three gives all three a wrong answer.

This post works through what retiring early actually requires in each of those three places, using verified 2026 numbers, the actual research the 4% rule is based on, and a framework you can use regardless of which side of the Atlantic you are on. It is longer than most posts on this subject because the subject deserves it.

The three inputs that matter

Every early retirement plan comes down to three numbers.

The first is annual spending in retirement. Not income. Not salary. Spending. This is almost always the number people get wrong, because they either extrapolate from their current salary ("I earn £60k, so I'll need £48k in retirement") or they lowball it because saying a smaller number makes the target look achievable. Both are mistakes. The only reliable way to estimate retirement spending is to look at what you actually spend today, subtract the things that genuinely go away (mortgage, commuting, childcare if relevant), and be honest about the things that do not (food, utilities, insurance, holidays, healthcare in the US, helping adult children, replacing the boiler).

The second is the length of retirement. Someone retiring at 65 with a 25-year horizon is playing a different game from someone retiring at 50 with a 40-year horizon. Almost all published safe withdrawal rate research targets 30 years. If you are planning for more, you need to adjust.

The third is expected real return after inflation. This is where most amateur calculations go sideways. People plug in 7% because that is roughly the historical US stock market number, forget that inflation averages around 2.5-3%, and end up with a plan that assumes real returns of 7% rather than 4%. Those two assumptions produce wildly different answers over a 30-year horizon.

With those three inputs, the basic calculation is straightforward. Take your annual spending, divide by a sustainable withdrawal rate, and you have your target portfolio. The trouble starts when you look at what a sustainable withdrawal rate actually is.

The 4% rule, as it actually exists

The "4% rule" traces back to a 1994 paper in the Journal of Financial Planning by William Bengen, titled "Determining Withdrawal Rates Using Historical Data." Bengen looked at US stock and bond returns from 1926 onwards and asked a specific question. If a retiree took out a fixed percentage of their starting portfolio each year, increased that amount for inflation, and held a 50/50 mix of US large-cap stocks and intermediate-term government bonds, what was the highest starting withdrawal rate that would have survived every 30-year period on record?

His answer was 4.15%, which in the paper got rounded to 4%. This was his "SAFEMAX", meaning the maximum safe withdrawal rate in the worst historical scenario. The 1998 paper by Cooley, Hubbard, and Walz, widely known as the Trinity Study, expanded the work using Ibbotson data for 1926-1995 and reframed it in terms of "success rates." They found a 4% withdrawal rate had a 95% success probability over 30 years with a stock-heavy portfolio.

Two things are worth noting about both studies. They covered 30 years only. They used US data only. Bengen himself has since updated his own number twice. In 2006 he revised it to 4.5% based on broader asset allocation. More recently, in interviews promoting his 2025 book, he identified 4.7% as his new SAFEMAX, acknowledging that his earlier work used too narrow an asset mix.

So the original author of the 4% rule now thinks 4.7% is closer to right for a US retiree, while newer research from Morningstar, working forward rather than backward, currently puts the number at 3.9% for 2026. The range that sits around "the 4% rule" is actually 3.5% to 4.7% depending on who you ask and what year they said it.

Now for the part that rarely gets mentioned in FIRE content.

What happened when researchers looked outside the US

In 2010, Wade Pfau, then at the National Graduate Institute for Policy Studies in Tokyo, replicated Bengen's methodology across 17 developed-market countries using the Dimson, Marsh and Staunton dataset covering 1900-2008. His paper "An International Perspective on Safe Withdrawal Rates: The Demise of the 4 Percent Rule?" appeared in the Journal of Financial Planning that December.

The findings were uncomfortable. With a 50/50 stock-and-bond portfolio, the 4% rule did not survive in any of the 17 countries over the worst 30-year historical window. Even with an artificially generous "perfect foresight" assumption that let each country pick the best-performing asset allocation after the fact, only five markets had a SAFEMAX of 4% or higher: Sweden, Canada, New Zealand, Denmark, and the United States.

For the specific countries most relevant to European readers, Pfau's numbers were sobering. The UK's SAFEMAX with a 50/50 stocks-and-bonds portfolio was around 3.05% in one iteration, and 3.43% in the stocks-and-bills version. Germany, France, Italy, Spain, and Belgium all produced SAFEMAX values below 3%. Italy saw the 4% rule fail in 80.5% of rolling 30-year periods. Japan, affected by its post-war inflation shock, produced a SAFEMAX of 0.47%.

This does not mean a UK or European retiree should plan on a 2% withdrawal rate. What it means is that the 4% rule, treated as universal, produces a materially higher risk of failure outside the US than inside it. The reasons are straightforward: higher historical inflation volatility, lower real equity returns, and less favourable bond market behaviour over long periods.

The practical implication for this post is that the same £1 million portfolio supports a different level of sustainable spending depending on where you live, even if you invest in globally diversified index funds.

UK example: retiring at 55 with £40,000 a year of spending

Let us work through a specific case. Take a 45-year-old in the UK, currently spending around £40,000 a year after housing costs, aiming to retire at 55 with the same lifestyle maintained in real terms.

Step 1: Pension access and state pension. The UK minimum pension access age is 55 until April 2028, when it rises to 57. A 45-year-old planning to retire at 55 today will be affected by the 2028 change and will need to wait until 57 to access a SIPP. State pension age for anyone born after April 1977 will be 68, though for those born earlier it is 67. For the 2026/27 tax year the full new state pension is £241.30 a week, or £12,548 a year, after 35 qualifying National Insurance years. Verified against HM Government data.

Step 2: Sustainable withdrawal rate. Using Pfau's UK figures and adjusting for a 35-year retirement rather than 30, a conservative starting withdrawal rate of 3.0% to 3.25% is defensible. A retiree willing to accept some spending flexibility and a small probability of running down the pot could push towards 3.5%. We will use 3.25% as the baseline.

Step 3: State pension offsets. At 67, the full state pension of £12,548 a year (2026/27) will offset part of the spending need. Between retirement at 55 and state pension at 67, the full £40,000 has to come from the portfolio. From 67 onwards, the portfolio needs to cover only £27,452 per year (£40,000 minus £12,548 state pension, assuming the pension keeps pace with price or wage inflation via the triple lock).

Step 4: The bridge. Between 55 and 57, no SIPP access. The gap has to be covered by ISA, GIA, or Lifetime ISA (available from 60). Two years of £40,000, assuming no growth during drawdown, means roughly £80,000 in ISA or GIA at retirement.

Step 5: The main pot. Using a 3.25% SWR on the £40,000 annual need produces a target of about £1,230,000 in total retirement assets. Adjusting down for state pension from 67, the effective target is slightly lower because the portfolio only needs to fund £40k for 12 years and £27,452 for the remaining years. A rough calculation, treating the pot as one pool, lands around £1.05 million to £1.15 million depending on assumptions about state pension real-term sustainability.

The realistic UK target, for someone wanting £40,000 a year of real spending from age 55 with modest state pension support, sits between £1.1 million and £1.3 million, split across a SIPP (for the post-57 phase) and an ISA (for the 55-57 bridge and supplementary tax-free withdrawals thereafter). The 2026/27 tax year offers a £20,000 ISA allowance and a £60,000 SIPP annual allowance, so building that split across both wrappers is plausible for a determined saver over 15-20 years.

EU example: retiring at 50 with €35,000 a year, using Germany as the template

A 38-year-old in Germany, aiming to retire at 50, spending €35,000 a year, is facing a harder version of the same problem. Germany is used here as the illustrative case because its system is reasonably representative of continental Europe and because Pfau's historical data covers it directly. Specific numbers vary meaningfully in France, the Netherlands, Italy, and Spain, and a country-by-country treatment would need its own post.

Step 1: Retirement horizon. Retiring at 50 against a statistical life expectancy of 85 means planning for a 35-year retirement, potentially longer if you are targeting a healthy buffer.

Step 2: State pension. Germany's regular retirement age is rising gradually from 65 to 67. A 50-year-old retiree has 17 years to wait before drawing any state pension (Gesetzliche Rentenversicherung). The amount received depends on "Entgeltpunkte" accumulated through working years. Unlike the UK flat-rate pension, it is earnings-linked.

Step 3: Withdrawal rate. Pfau's German SAFEMAX in the original 1900-2008 dataset was below 3% for a 50/50 portfolio. This reflects German experience through two world wars and the inflation events that followed. A modern retiree with globally diversified equity exposure (via UCITS ETFs tracking MSCI World or FTSE All-World) is not purely exposed to German market history, which softens the comparison. Even so, 3.0% is a sensible conservative baseline for a 35+ year horizon in a non-US market. Some German FIRE commentators work with 3.25-3.5% as a central case, acknowledging the sensitivity to long-run equity assumptions.

Step 4: The target. €35,000 divided by 3.0% produces a target portfolio of approximately €1.17 million. Adjusting upward for the state pension arriving at 67 (17 years into retirement) trims this modestly. Adjusting downward for tax friction (Abgeltungsteuer at 25% on investment income, with the €1,000 Sparerpauschbetrag annual allowance) pushes it back up.

Step 5: The wrapper question. Germany lacks an ISA equivalent. The typical German FIRE portfolio lives in a regular brokerage account with UCITS ETFs, subject to Abgeltungsteuer. Riester and Rürup exist but have limited application to early retirement. This is a meaningful structural disadvantage compared to UK and US savers and is part of the reason German FIRE requires a larger pot for equivalent after-tax spending.

The realistic German target for €35,000 a year of spending from age 50 sits between €1.2 million and €1.4 million, with the higher end reflecting both the long horizon and the tax drag from an unwrapped brokerage portfolio. Equivalent numbers for France would centre around PEA (tax-efficient after 5 years, equities only, €150,000 cap) and assurance-vie (tax-advantaged after 8 years). Equivalent numbers for the Netherlands would factor in the box 3 wealth tax treatment. The broad point is that continental European retirees typically need a larger pot for the same spending level than UK or US retirees.

US example: retiring at 50 with $60,000 a year

A 42-year-old in the US, spending $60,000 a year, targeting retirement at 50.

Step 1: Horizon. Retiring at 50 with a long life expectancy means planning for 40-plus years.

Step 2: Social Security. Full Retirement Age is 67 for anyone born in 1960 or later, officially reached in November 2026. Claiming at 62 brings a permanent reduction of roughly 30%. Waiting to 70 produces a roughly 32% bump above FRA. The average Social Security retirement benefit in 2026 is around $2,071 a month, or approximately $24,852 a year. A high earner who contributed at the taxable maximum throughout their career and claims at 70 could reach $5,181 a month ($62,172 a year) based on SSA 2026 data. For a middle-income saver targeting retirement at 50, assuming something close to the average benefit is reasonable.

Step 3: The bridge and the ladder. US savers face a harder bridge problem than Europeans on one axis and an easier one on another. Harder because 401(k) and traditional IRA access attracts a 10% early-withdrawal penalty before 59½. Easier because the Roth conversion ladder, Roth IRA contribution withdrawals, and 72(t) SEPP payments all provide legal early-access routes. A typical FIRE strategy involves building a taxable brokerage account alongside the 401(k) and Roth IRA so that the 50-to-59½ bridge can be funded from post-tax assets.

Step 4: Healthcare. This is the variable that matters most and the one with no UK/EU equivalent. Between retirement at 50 and Medicare eligibility at 65, a US early retiree is responsible for their own health insurance. ACA marketplace plans can be affordable for those with low taxable income in retirement (because subsidies phase out with income), but the cost of care, not just premiums, can be significant. A realistic assumption is that a US early retiree needs to budget an additional $10,000 to $20,000 a year for healthcare between 50 and 65, depending on state, income, and health status. For this example, assume $12,000 a year added to the $60,000 baseline, producing $72,000 a year needed for the 15-year healthcare-gap phase.

Step 5: The withdrawal rate. US data has historically supported higher withdrawal rates than any other country except Canada. Using Morningstar's 2026 forward-looking number of 3.9% for a 30-year horizon, and reducing to around 3.5% for a 40-year horizon (Morningstar's own base case for 40 years is 3.3%), a mid-3% figure is defensible. Bengen's updated 4.7% assumes the same backward-looking historical methodology that produced the original 4%. We will use 3.5% as the baseline here.

Step 6: The target. Using 3.5% on $72,000 during the healthcare-gap phase produces a peak need of approximately $2.06 million. This is probably overstating it because the need drops to $60,000 after 65 and Social Security knocks perhaps $25,000 off the portfolio-drawn figure from 67 onwards. A more nuanced multi-phase calculation lands somewhere between $1.7 million and $1.9 million for the total pot at retirement.

The realistic US target for $60,000 a year of spending from age 50 sits between $1.7 million and $2 million. Someone retiring earlier, with higher healthcare costs, or without Social Security earnings credits will need more. Someone retiring at 55 with a shorter healthcare gap will need less.

What the three examples have in common

Three different countries, three different tax systems, three different state pensions, three different healthcare pictures. The headline targets are £1.1-1.3 million, €1.2-1.4 million, and $1.7-2.0 million respectively. At today's exchange rates, these are closer to each other than a naive exchange-rate conversion suggests, because the underlying spending levels are deliberately chosen to reflect broadly comparable lifestyles in each country.

What they share is a structure. Every early retirement plan, anywhere in the world, needs to answer five questions:

1. What is your actual annual spending in retirement, honestly estimated?
2. How long is the retirement?
3. What sustainable withdrawal rate fits your market, horizon, and risk tolerance?
4. What state or social security benefits will offset the portfolio drawdown, and at what age?
5. What bridge strategy covers the years between retirement and the earliest access to tax-advantaged retirement accounts or state pensions?

The last question is the one most commonly skipped. UK retirees focused on SIPP totals forget that they cannot access the SIPP for years. US retirees focused on 401(k) balances forget the 10% penalty before 59½ and the 15-year healthcare gap. European retirees frequently lack the tax-wrapper machinery that makes bridging cheap in the UK and US. A plan that passes the "total pot" test but fails the bridge test is not a plan.

Three things every calculator gets wrong

One: the single-number fallacy. Every retirement calculator ends with one number. Real retirement spending will not match that number in any given year. A number that works at average inflation fails at 4% inflation. A number that works with average returns fails if the first five years of retirement are bad ones (sequence of returns risk, which deserves its own treatment and will get one). The output of a calculator is a midpoint in a distribution of possible outcomes, not a target to hit exactly.

Two: ignoring the bridge. A pension or 401(k) balance at age 50 is not the same as a spendable portfolio at age 50. If you are reading financial-independence content and the calculator asks only for your total net worth, it is giving you a number that is wrong in a specific direction, which is to say too optimistic.

Three: assuming the 4% rule. The 4% rule is the most widely cited and least universally applicable number in personal finance. It is based on US historical data from a period during which US equity markets performed exceptionally well by global standards. Using it unchanged as a non-US retiree overstates sustainable spending by 15-25% on the historical evidence. Even for US retirees, current forward-looking research puts the number closer to 3.9% than 4%.

Modelling this properly

Working through the kind of calculation above in a spreadsheet is tedious, and most spreadsheets end up oversimplifying either the bridge problem, the tax treatment, or the sequence risk. This is part of why Endute includes a FIRE planning module. It handles multi-phase retirement (accumulation, bridge, pension, later-life), lets you set different withdrawal rates and assumptions per phase, runs sensitivity analysis to show which variables your plan is most dependent on, and supports UK, EU, and US tax wrappers as separate accounts with their own rules.

This is also worth being direct about: Endute is a personal finance management app. The FIRE tools sit alongside the day-to-day features most users come for, which are open banking aggregation, spending analysis, budgeting, net worth tracking, and investment monitoring. The planner is a feature for people who want it, not the whole product.

If you want to see your own version of the calculation this post describes, you can sign up at app.endute.com and work through it against your actual accounts. No gating, no email capture required to access the tool.

The honest summary

Retiring early is achievable for more people than most headline "how much do I need to retire" content suggests, and harder for more people than most FIRE content suggests. The honest position sits between those two. The target number depends on your country, your wrappers, your horizon, and your willingness to stay flexible during retirement rather than commit to a fixed withdrawal percentage from day one.

The 4% rule was a useful starting point in 1994. It has since been updated by its own author, modified by subsequent research, and shown to be too aggressive outside the US. Treat it as a rough anchor, not a target. Work your own numbers with your own spending, your own tax situation, and your own retirement age. Stress-test them against adverse scenarios. Then revisit them every year, because a plan that is not updated is a plan that quietly goes wrong.

Three numbers to hold in your head as you go. Roughly £1.1-1.3 million for a UK retiree wanting £40,000 a year from 55. Roughly €1.2-1.4 million for a German retiree wanting €35,000 a year from 50. Roughly $1.7-2 million for a US retiree wanting $60,000 a year from 50 with healthcare included. These are not your numbers. Yours will differ, probably meaningfully. The framework is what carries over. The arithmetic is just arithmetic.

Sources and verification

All current-year figures in this post are from official or authoritative sources as of April 2026:

• UK new state pension 2026/27: £241.30/week, £12,548/year. Source: Department for Work and Pensions statutory review, 26 November 2025; gov.uk.
• UK ISA allowance 2026/27: £20,000. UK SIPP annual allowance: £60,000. Source: HMRC / Fidelity UK / AJ Bell.
• UK personal allowance 2026/27: £12,570. UK CGT annual exempt amount: £3,000. UK dividend allowance: £500. Source: HMRC / gov.uk / ATT.
• UK minimum pension age: 55, rising to 57 in April 2028. Source: gov.uk / Standard Life.
• US 401(k) limit 2026: $24,500. IRA/Roth IRA limit: $7,500. Source: IRS Notice 2025-67.
• US Social Security full retirement age: 67 for those born 1960 or later. Source: SSA.
• US Social Security average 2026 benefit: $2,071/month. Max at FRA: $4,152/month. Max at 70: $5,181/month. Source: SSA.
• 4% rule original research: Bengen, William P. (1994). "Determining Withdrawal Rates Using Historical Data." Journal of Financial Planning, 7(4): 171-180.
• Trinity Study: Cooley, P. L., Hubbard, C. M., & Walz, D. T. (1998). "Retirement Savings: Choosing a Sustainable Withdrawal Rate." AAII Journal.
• International SWR research: Pfau, W. D. (2010). "An International Perspective on Safe Withdrawal Rates from Retirement Savings: The Demise of the 4 Percent Rule?" Journal of Financial Planning, December 2010. UK SAFEMAX figures from this paper and subsequent updates, including Pfau's 2014 work on international diversification.
• Morningstar 2026 SWR: 3.9% base case for 30-year horizon, 3.3% for 40-year horizon. Source: Morningstar, "The State of Retirement Income: 2025," December 2025.
• Bengen updated figures: 4.5% in 2006, 4.7% in 2025 book. Source: Bankrate interview with Bengen, 2025.