How do I calculate FIRE across multiple currencies?

Convert every account into the currency you plan to retire in, then apply the usual 25× annual expenses (4% rule) to your expenses in that same currency. The hard part is the conversion — exchange rates move — so model a range of FX scenarios rather than assuming today's rate holds for decades.

Which currency should my FIRE number be in?

The one you'll spend in during retirement. If you'll live in the eurozone, your FIRE number is in euros and your non-euro holdings are exposure to manage. Picking your retirement currency early makes every other decision — where to hold savings, when to convert — much clearer.

How much does exchange-rate risk affect my FIRE timeline?

If more than about 30% of your wealth is in a currency other than your target retirement currency, FX swings can move your timeline by a year or more in either direction. The closer you get to FIRE, the more it's worth gradually consolidating toward your retirement currency to reduce that risk.

Should I use a lower withdrawal rate for international FIRE?

Many internationally mobile savers use 3.25-3.5% instead of the classic 4%, to account for currency risk, cross-border tax uncertainty, and potentially higher healthcare costs abroad. The trade-off is a larger target: dropping from 4% to 3.5% raises the corpus you need by roughly 14%. Run the numbers both ways and see how much it moves your date.

How do I track a multi-currency FIRE portfolio over time?

Use a tracker that aggregates accounts across banks and currencies and converts everything to one base currency in real time. Wealthos connects to European banks, handles multi-currency conversion automatically, and forecasts your net worth — so your FIRE progress stays accurate without spreadsheet upkeep.

Wealthos

Multi-Currency FIRE Calculator

Reach financial independence when your savings span EUR, USD, GBP and more. Most FIRE calculators assume one currency — this one models the reality of a cross-border portfolio.

Current savings€90k

Monthly savings€2,700

Monthly expenses€3,800

Expected annual return6.5%

Safe withdrawal rate4%

FIRE Number

€1.1M

Years to FIRE

16 yr

Savings Rate

42%

Why single-currency FIRE maths breaks

The 4% rule was derived from a single market, a single currency and a single tax system. Hold assets in four currencies and spend in a fifth and the arithmetic quietly stops describing your situation. The problem is not that currencies move; it is that the movement is invisible in an unconverted total. A portfolio spread across euros, sterling and francs can appear to grow in a year when none of the underlying balances changed, purely because the reference rate moved. Convert everything into one currency before you compare anything to a target, and use a published reference rate rather than whatever your bank happened to offer on the day.

Sources: ECB euro reference exchange rates

Choosing the currency to retire in

The right reference currency is the one your future spending will be denominated in, and choosing it early makes every later decision simpler. If you intend to retire in Portugal, the euro is your unit of account even while you are paid in francs, and a strong franc year is a windfall rather than progress. This matters most in the last few years before you stop working. A portfolio you are about to draw down cannot wait out a 15% adverse currency move the way a portfolio with twenty years left can, which is why mobile savers typically shift toward the target currency as the date approaches rather than staying diversified for its own sake.

Sources: ECB euro reference exchange rates

Savings rate beats currency timing

Nobody has a reliable edge in predicting exchange rates, and trying to time conversions is a good way to turn a savings plan into a trading strategy. What you can control is how much reaches the portfolio and how little the journey costs. Convert on a schedule rather than on a hunch, so you average across rates instead of betting on one. Compare providers before large transfers: on €20,000 the difference between a 0.4% and a 1.5% spread is €220, and a household converting €2,500 a month at 1% loses €300 a year that would otherwise compound. Those are certain savings, unlike any view you hold on the currency itself.

Sources: ECB euro reference exchange rates

How exchange rates move a FIRE date

Formula

FIRE number = Annual spending in your target currency ÷ Withdrawal rate

Convert every holding into the currency you plan to spend in before you compare anything to your target. Assets left in their native currency flatter or flatten the total depending on the day's rate, and the error compounds over a decade. The calculator converts first, then projects the combined total forward with contributions and growth.

Worked example

Ana holds €120,000 in a Dutch broker, £40,000 in a UK ISA and CHF 25,000 in a Swiss account. Converted at today's rates that is roughly €193,000. She wants €40,000 a year in Portugal, so her FIRE number at 4% is €1m. A 10% move in sterling against the euro shifts her total by about €4,600 — small now, but a 10% move against a €600,000 portfolio is €60,000.

Make better financial decisions

Hold the currency you will spend in as you approach the date. Currency risk matters far more on a portfolio you are about to draw down than on one with twenty years left to recover.
Do not confuse a rate move with progress. A weaker home currency can inflate a converted total without a euro of new saving behind it.
Watch conversion costs on regular transfers. A 1% spread on €3,000 a month is €360 a year that never reaches the portfolio.
Keep an emergency fund in the currency you spend day to day, whatever the rest of the portfolio is denominated in.
Re-check the conversion at least quarterly. A number that was right in January is simply a different number by June.

See what a rate move does to your FIRE date

This is one snapshot at today's rates. Wealthos converts every account at live rates, so your progress reflects real saving rather than whichever way the currency moved this month.

This calculator needs no account and nothing leaves your browser. Wealthos offers you a 7-day free trial to try the product.

For expats in Europe

Track your FIRE number across every currency

Wealthos consolidates your accounts across banks and currencies into one live net worth, so your FIRE progress stays accurate automatically. Free, no card.

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