If you’ve ever Googled “how much can I safely take from my pension each year?”, you’ve almost certainly bumped into the 4% rule. It’s the most quoted piece of retirement maths in the world — and most of the people quoting it are sat in America, drawing dollars, paying US tax, and not buying their olive oil in euros.

So what does it actually mean for a UK expat living in Portugal in 2026? Does the same rule of thumb hold up when you’re juggling sterling pensions, euro spending, NHR-or-no-NHR tax, and a market that has had quite the wobble? In my experience working with British retirees up and down the Algarve, the honest answer is: yes, the 4% rule is still a useful starting point — but only if you understand what’s under the bonnet and where it tends to break down for cross-border retirees. This guide unpacks all of that, in plain English.

What is the 4% rule, in one paragraph?

The 4% rule comes from a 1994 study by US financial planner William Bengen. He looked at historical investment returns and asked: how much could a retiree withdraw each year from a balanced portfolio without running out of money over a 30-year retirement? His answer was around 4% of the portfolio in the first year, then increasing that pound amount each year by inflation. So a £500,000 pension would generate £20,000 in year one, then £20,600 the next year if inflation was 3%, and so on — regardless of what markets did.

It’s elegant, it’s memorable, and it’s been repeated so often that many people now treat it as gospel. It is not gospel. It’s a starting point, built on a particular set of assumptions about asset mix, tax, currency, and time horizon. Change those assumptions — which moving to Portugal absolutely does — and the rule needs adjusting.

Why the 4% rule needs translating for UK expats in Portugal

Bengen’s study assumed an American retiree, holding US assets, spending US dollars, paying US tax, retiring at 65 with a 30-year horizon. Take any one of those assumptions and change it, and the safe withdrawal rate moves. UK expats in Portugal change most of them.

Here are the big differences that matter:

• Currency mismatch. Most British retirees hold sterling pensions but spend in euros. A 10% slide in GBP/EUR is, for spending purposes, equivalent to a 10% portfolio loss — even if the underlying funds haven’t moved an inch.
• Longer life expectancy. A 60-year-old British woman has a roughly one-in-four chance of reaching 95. Portugal’s clean air, Mediterranean diet and walkable lifestyle don’t shorten that. The original 4% rule assumes 30 years; many of my clients need to plan for 35 or even 40.
• Tax rates differ. NHR (or its 2.0 successor) can shelter pension income at low rates, but the regime is time-limited. Once you fall back into the standard Portuguese tax brackets, the same gross withdrawal supports a much smaller net spend.
• Earlier retirement. Lots of expats retire in their late 50s or early 60s. A 35-year retirement is a much bigger ask of a portfolio than 30 years.
• Different asset mix. Bengen modelled a 50/50 US stock/bond portfolio. UK and global investors typically hold a different mix, with home bias toward the FTSE and gilts.

None of this means the rule is useless. It just means we need to apply it with our eyes open.

What withdrawal rate is actually safe for a UK expat in Portugal?

Modern updated studies — including work from Morningstar and from researchers like Wade Pfau, who looked specifically at international retirees — suggest a starting withdrawal rate of around 3.3% to 4% is reasonable for a globally diversified portfolio over a 30–35 year horizon, depending on the asset mix and the starting point of valuations.

For a UK expat in Portugal, my working rule of thumb in 2026 looks like this:

1. Plan for a longer retirement. Use 35 years as a base case if you retire at 60, and 40 years if you retire earlier or are in good health.
2. Start at 3.5% rather than 4%. The extra cushion absorbs currency drift, longer life expectancy, and the possibility that the next decade of returns isn’t as kind as the last.
3. Be willing to flex. A static “spend the same in real terms forever” rule is mathematically tidy but emotionally unrealistic. In bad market years, trim spending by 10–15%. In good years, allow a small rise. This single change — called a “guardrail” approach — can support a noticeably higher starting rate.
4. Hold 1–2 years of euro spending in cash. If markets fall, you spend the cash, not the equities. The portfolio gets time to recover.
5. Recheck annually. Look at your portfolio value and your remaining time horizon every January. If markets are up and you’re a year older, you can often nudge spending up. If markets are down, hold steady.

The currency factor: the bit Bengen never had to worry about

This is the issue I see catch out more retirees than any other. You retire with a £750,000 SIPP. Sterling is at €1.18. Your £30,000 a year withdrawal supports a €35,400 lifestyle. Two years later sterling is at €1.08. Same £30,000 withdrawal now buys you €32,400 — you’ve taken a quiet 8.5% pay cut without lifting a finger.

There are several practical ways to manage this:

Match your investments to your spending currency where it makes sense. Holding some euro-denominated assets — whether through globally diversified funds, euro bonds, or simply euro cash buffers — reduces the gap between what you earn and what you spend.

Use forward contracts or limit orders for big transfers. If you know you’ll need €40,000 next April, you don’t have to gamble on the rate. A currency broker can lock in today’s rate for a future delivery, often at better margins than your bank.

Don’t try to time the market. Most retirees who try to “wait for sterling to come back” end up not transferring at all. Steady, scheduled transfers usually beat trying to be clever.

For more detail on protecting your pounds when they’re funding a euro lifestyle, our earlier guide on currency risk for UK expats goes deeper.

How tax in Portugal changes the maths

The 4% rule talks about gross withdrawals. What lands in your bank account after tax is what actually pays the bills. Portugal’s tax position for foreign pension income has shifted meaningfully since the original NHR was scrapped in 2024 and replaced with NHR 2.0 (officially the Tax Incentive for Scientific Research and Innovation). Most retiring pensioners do not qualify for NHR 2.0, which is targeted at researchers and skilled professionals.

That means new retirees moving to Portugal in 2026 are typically taxed under the standard Portuguese progressive income tax rates — which run from 13.25% up to 48% — on their pension income, with the UK–Portugal Double Taxation Treaty allocating taxing rights between the two countries. Expats already enjoying the original NHR regime keep that benefit until their 10 years are up; after that, they too move into the standard system.

The practical implication for your withdrawal rate: a gross 4% withdrawal might leave you with a net 3% or so once Portuguese tax has had its share, depending on your bracket. That’s worth modelling carefully before you commit to a spending number. The official guidance is on the Portuguese tax authority website, although it is largely in Portuguese.

Sequence-of-returns risk: the silent assassin

Two retirees can earn the same average return over 25 years and end up with wildly different outcomes — if the order of those returns is different. This is “sequence-of-returns risk”, and it bites hardest in the first 5 to 10 years of retirement, when the portfolio is largest.

A simple example: imagine you retire with £500,000 and start drawing £20,000 a year. If markets fall 25% in your first two years, you’ve now got £320,000 or so — and your £20,000 withdrawal is suddenly 6.25% of the portfolio rather than 4%. Even if markets recover handsomely afterwards, the maths may never quite catch up.

This is why the simple guardrail behaviour matters so much. Cutting that £20,000 to £17,000 for two or three bad years, or holding off on big one-off spends in a downturn, can make the difference between a portfolio that lasts and one that runs dry in your late 80s. It’s also why I rarely recommend a 100% equity portfolio in the first decade of retirement, even when clients have the risk tolerance for it.

How to stress-test your own number

Before you commit to a withdrawal rate, run your plan through three simple stress tests.

Test one: the bad start. Assume your portfolio falls 30% in the first two years. Can you keep your lifestyle going while reducing spending by 15% for three years? If yes, you have built-in flexibility. If no, your starting rate is too high.

Test two: the long retirement. Run the numbers on living to 95 or 100. If the plan only just survives a 30-year horizon, it won’t survive a 38-year one.

Test three: the strong euro. Model GBP/EUR at €1.05 for a sustained period. Does the spending plan still work? If your lifestyle only stacks up at today’s rate, you’re effectively making a currency bet you may not realise you’ve taken.

If any of those tests cause the plan to fall apart, the answer isn’t usually to abandon retirement — it’s to start at 3.5% rather than 4%, hold a bigger cash buffer, or be more disciplined about flexing spending.

Frequently Asked Questions

Is the 4% rule really safe in 2026?

For a UK retiree in Portugal with a 30-year horizon and a balanced global portfolio, 4% is on the upper edge of what most modern studies consider safe. I’d treat it as a ceiling rather than a target. Starting at 3.3% to 3.7% with a willingness to flex spending is more realistic given longer life expectancy and currency risk.

Does the 4% rule include tax?

No. It refers to gross withdrawals from your pension or investment portfolio. You then pay income tax in your country of residence — in Portugal’s case, at the standard progressive rates unless you’re under the original NHR regime. Always model net spending power, not gross withdrawals.

Should I take more from my pension in good years?

Within reason, yes. The “guardrails” approach allows you to nudge spending up after years where the portfolio has grown faster than expected, and trim it down after bad years. This adaptability typically supports a higher starting rate than a fixed real-terms withdrawal would.

Does the 4% rule work for early retirees?

Less reliably. The original study assumed a 30-year retirement. If you’re retiring at 55, you may need 40 years of income. Most analysts suggest a starting rate closer to 3% to 3.3% in that case, plus building in flexibility.

How does the 4% rule apply to a UK SIPP I keep in pounds?

The percentage works the same way, but you must layer currency risk on top. Practically, that means either holding some euro-denominated investments to match euro spending, holding a euro cash buffer, or being prepared to reduce withdrawals when sterling weakens.

What to Do Next

The 4% rule is a useful starting point, not a finish line. For UK expats in Portugal, a sensible 2026 plan starts at 3.5%, builds in a euro cash buffer, accepts that spending will need to flex with markets and currency, and gets stress-tested against bad starts and long lives.

If you’d like to discuss how this affects your personal situation — including a proper cash-flow forecast in both pounds and euros — get in touch with our team. We specialise in helping UK expats in Portugal turn pensions and investments into a sustainable, tax-efficient retirement income.

Matthew Renier is a Chartered Financial Adviser at Arthur Browns Wealth Management, based in the Algarve, Portugal. He has over 20 years of experience helping British expats manage their pensions and financial planning across borders.

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