What Exchange Rate Do I Use for My French Tax Return? (2026)

Every item of foreign income on a French tax return must be declared in euros. But there is no single official rate — and using the wrong one, or applying it backwards, is one of the most common errors on UK expat returns.

The golden rule: you must convert all foreign income into euros using either the official exchange rate on the day the money was received or hit your account. It is generally accepted that average annual rates are used for regular, repeating income like pensions.

For an overview of everything else you need to declare, see our guide to how the French tax system works.

The Official Source — Banque de France

The definitive reference for the French tax authorities is the Banque de France, which publishes daily exchange rate parities aligned with the European Central Bank.

There is no single "official tax return rate sheet" published by the French tax office (DGFiP) for every world currency. The rate varies constantly based on the date of your transactions. The Banque de France statistics portal is the authoritative source for historical daily rates — not Google, not bank comparison sites, not random currency converters.

The Taxpert data page is built using the full set of historical daily rates for the main currencies used by UK expats — GBP, USD, CHF and CAD — updated annually.

Two Methods — Which One Applies to You

Method 1 — The Daily Rate (Cours du jour)

This is the legal default under the French tax code. You use the Banque de France rate on the exact date the income was received.

Use this for:

• Capital gains from selling shares or property
• Pension lump sums
• Irregular or one-off payments
• Dividends
• Any large or non-recurring payment

For these income types, the precise conversion matters. Using an annual average on a large capital gain or lump sum could meaningfully change the figure — and the DGFiP expects the daily rate for exceptional income.

Method 2 — The Average Annual Rate (Taux moyen)

This uses a single rate for the entire calendar year, applied to your total annual income in that currency. It is technically an administrative concession (tolérance administrative) — officially tolerated in practice for regular, steady income streams.

Use this for:

• Regular salaries
• Monthly or four-weekly pensions
• Regular interest payments

The tax office recognises that calculating individual conversion rates for 12 or 52 payment dates is impractical for most households. The average rate is widely accepted for recurring income — but it remains a concession, not a right. If the DGFiP ever queries a return, the daily rate is the defensible position.

There is also a third option for pension holders with a French bank account — see below.

The Four-Weekly Pension Problem

The UK State Pension is paid every four weeks — not monthly. That means 13 payments per year, each on a slightly different date, each with a potentially different exchange rate.

You have two practical approaches:

Option A — Use the annual average rate (simplest) Add up all 13 payments in pounds sterling, then multiply the total by a recognised annual average rate. One calculation, done.

Option B — Use the actual euro amounts received (most accurate) If your pension is paid directly into a French bank account, your bank converts the sterling to euros at the moment of receipt. In this case, do not look at the exchange markets at all. Simply log into your French bank account, add up the exact euro amounts that actually landed across the 13 payment dates, and declare that total.

Your bank statement is your primary source document. The conversion has already been done for you — and it reflects the actual rate applied to your money, not an approximation.

This is the cleanest approach if your pension lands in a French account. It is accurate, auditable, and requires no rate-lookup at all.

What If the Exact Date Isn't Available?

The Banque de France does not publish rates on weekends or public holidays. If your income arrived on a Saturday, Sunday, or bank holiday, the standard rule is: use the rate from the last available business day — typically the Friday immediately before, or the preceding working day if the Friday was also a holiday.

This is a well-established convention and the DGFiP will not question a return that applies it consistently.

Where to Find Reliable Rates

Avoid using random currency conversion websites — many show mid-market rates that don't match the Banque de France parities, and some quote inverse rates that will produce incorrect figures.

Use these sources:

1. The Banque de France Statistics Portal The absolute primary source for historical daily and monthly rates. Available at webstat.banque-france.fr. Slightly technical to navigate but authoritative.

2. The Taxpert Data Page The Taxpert data page publishes the full set of historical Banque de France daily rates for GBP, USD, CHF and CAD — searchable by date, ready to use directly on your return. See the exchange rates section on the Taxpert reference data page →

3. Your Own French Bank Statement If your foreign income is paid into a French bank account and converted on receipt, your statement is your best source. The euro amount shown is the converted figure at the rate applied by your bank on that date.

4. Taxpert's Filing Assistant Taxpert's filing assistant does the conversion automatically. Import your bank transactions and the correct Banque de France rate is applied to each payment date — no manual rate lookup required.

The Most Common Exchange Rate Mistake

The biggest error is using the rate in the wrong direction — multiplying when you should divide, or accidentally picking up the inverse rate.

Exchange rates can be quoted two ways:

• £1 = €1.18 (how many euros per pound)
• €1 = £0.85 (how many pounds per euro)

If you have £10,000 in pension income and the rate is £1 = €1.18, you have €11,800. That is correct.

If you accidentally apply the inverse rate and divide £10,000 by 1.18 instead of multiplying, you get €8,475 — a difference of over €3,000 on a single income source. On a full year's income across multiple sources, this error compounds quickly.

A Note on Multiple Currencies

If you have income in more than one foreign currency — for example sterling from a UK pension and US dollars from an American investment account — each currency requires its own conversion using the relevant Banque de France rate for that currency. You cannot apply a single sterling rate to a mixed-currency income.

The Taxpert data page covers the main currencies used by UK expats. For less common currencies, the Banque de France statistics portal covers a wider range.

Common Mistakes

1. Using an internet rate converter instead of the Banque de France. Many sites show mid-market rates that do not match the official published parities. Always use the Banque de France rate or your own bank statement for a French bank account.

2. Applying the rate in the wrong direction. Converting £ to € should produce a larger number. If it doesn't, the rate has been applied backwards.

3. Using one arbitrary rate for all 13 pension payments. If you are using the daily rate method, each payment needs its own rate. If you want simplicity, use the annual average — but be consistent. Do not mix methods within the same income source.

4. Not using your French bank statement when the pension lands there. If your pension is paid into a French account and converted on receipt, the euro amounts on your statement are your most accurate and auditable source. Use them.

5. Using the wrong year's average rate. If you are using the annual average, make sure it is the rate for the tax year being declared (2025 income for the 2026 declaration). Last year's average rate is not interchangeable.

6. Not keeping records. Whether you use daily rates or the annual average, keep a record of how you calculated your euro totals — the rates used, the dates, and the source. If the DGFiP ever queries your return, a clear calculation trail is your best defence.

Frequently Asked Questions

What exchange rate should I use for my French tax return?

The legal default is the Banque de France rate on the date each payment was received. For regular, recurring income like pensions and salaries, the annual average rate is officially tolerated as a practical alternative. For one-off or large payments — lump sums, capital gains, dividends — use the daily rate.

Where do I find the official exchange rate for French taxes?

The Banque de France statistics portal (webstat.banque-france.fr) is the primary source. The Taxpert data page also publishes the full historical Banque de France daily rates for GBP, USD, CHF and CAD. Your French bank statement is also a valid source if your foreign income is paid into a French account and converted on receipt.

Can I use the annual average rate for my UK State Pension?

Yes — the annual average rate is officially tolerated for regular, repeating income like pensions. You total all 13 payments in sterling and multiply by the annual average rate. It is simpler than looking up 13 individual rates and is widely accepted in practice.

My pension is paid into my French bank account — do I still need to look up exchange rates?

No. If your foreign income is paid into a French bank account and converted by your bank on receipt, the euro amounts on your bank statement are your conversion source. Add up the actual euro amounts that landed in your account. The bank has already done the conversion — your statement is the record.

What do I do if my payment date falls on a weekend or bank holiday?

The Banque de France does not publish rates on non-business days. Use the rate from the last available business day before the payment date — typically the Friday before a weekend payment, or the preceding working day if that was also a holiday.

I have both a UK pension and US investment income — do I use the same rate for both?

No. Each currency requires its own separate conversion using the Banque de France rate for that specific currency. GBP and USD rates are different — they must be handled separately.