Multi-Currency Invoicing: VAT & GST Rules When Billing Across Borders
You can invoice in any currency you like — USD, EUR, GBP, whatever the client wants to see. But your tax authority only accepts one currency: your own. Every VAT and GST system in the world requires tax amounts to be calculated and reported in the domestic currency, which means every foreign-currency invoice has to be converted at some point. Which rate you use, which date the rate applies to, and what you print on the invoice are all rules — not choices.
This guide covers the UK, Canada, Australia, and the EU, because those are the systems most of our readers file under. (If you haven't read it yet, our guide to invoicing international clients covers the commercial side — currency choice, conversion fees, and payment methods.)
The core rule: tax is always reported in your home currency
Two separate things happen on a multi-currency invoice, and confusing them is where freelancers get into trouble:
- The commercial invoice — what the client sees and pays. This can be in any currency you and the client agree on.
- The tax calculation — the VAT or GST you owe your tax authority. This must be computed in your country's currency (GBP, CAD, AUD, EUR, etc.), even when the invoice itself is denominated in another currency.
That means every foreign-currency invoice needs a conversion step between "what the client pays" and "what goes on your tax return." The tax authorities care about three things: which rate you used, which date the rate applies to, and whether you did it consistently.
When does this actually come up?
If your exports of services to business clients abroad are zero-rated or outside the scope of your VAT/GST (which is the usual case — see the international invoicing guide), you may rarely owe tax on foreign-currency invoices at all. The conversion rules matter most when tax is chargeable:
- Domestic clients billed in a foreign currency. Some freelancers price in USD for clients at home. VAT/GST still applies in full, and the tax figures must be shown in domestic currency.
- EU freelancers billing EU consumers. Digital services and other B2C supplies within the EU are often taxed in the seller's country under OSS rules.
- UK freelancers billing UK clients in USD or EUR, or businesses in Northern Ireland dealing with EU clients.
UK: convert all VAT values to sterling
HMRC's rule (VAT Notice 700, section 16.4) is blunt: if you issue VAT invoices in a foreign currency, you must convert all values for VAT purposes into sterling. Specifically:
- The VAT amount must be shown in pounds sterling on the invoice itself — not just in your accounting.
- The net and VAT figures should be shown in sterling alongside the foreign-currency totals, so the client and HMRC can both see the tax position.
- The conversion uses the exchange rate at the tax point (usually the invoice date or date of supply, whichever creates the tax point first).
- Use a reasonable, published rate — such as the Bank of England spot rate or your bank's rate — and apply the same method consistently across invoices.
Worked example (illustrative rates): A UK freelancer invoices a UK client USD 2,500. Using an illustrative rate of 1 USD = 0.75 GBP, the sterling value is £1,875.00. At 20% VAT, the invoice shows VAT of £375.00 and a sterling total of £2,250.00, alongside the USD 2,500 the client actually pays. The £375.00 is what goes on the VAT return.
Details of UK VAT invoice requirements are in our UK VAT invoice guide.
Canada: Section 159 gives you a default — and alternatives
Canada's rule comes from Section 159 of the Excise Tax Act, with the detail filled in by GST/HST Memorandum 3-6:
- Default: the foreign currency is converted to Canadian dollars using the rate on the day the GST/HST becomes payable — the earlier of the day consideration is paid and the day it becomes due. For most invoices, that's the invoice date.
- Three pre-approved alternatives: the day consideration is actually paid, the day the foreign currency was acquired, or the average rate for the month in which tax becomes payable.
- Consistency is mandatory. Whichever method you choose, you must use it consistently for a reasonable period (about a year). You can't pick the most favourable rate per invoice.
- Acceptable rate sources: the source you actually converted through, the source you typically use, a Canadian chartered bank, the Bank of Canada, or the CBSA value-for-duty rate. A rate feed you don't actually trade through doesn't count.
- Your customer can use a different method — so the GST on your invoice and the input tax credit your customer claims can legitimately differ by a few cents.
Worked example (illustrative rates): A Canadian freelancer invoices a domestic client USD 1,000. Using the Bank of Canada rate on the invoice date — say 1 USD = 1.3655 CAD for illustration — the Canadian value is CAD 1,365.50, and 5% GST comes to CAD 68.28, reported in Canadian dollars. More detail on thresholds and provincial rates in our Canada GST/HST invoicing guide.
Australia: convert at the rate on the date of supply
The ATO requires GST to be reported in Australian dollars, and foreign-currency amounts are converted at the exchange rate applicable at the time of the supply:
- Use the rate on the date of the transaction or supply — the same day the GST liability arises.
- A published rate such as the Reserve Bank of Australia's daily rate, or your bank's rate on that date, is acceptable.
- Like every other system here, be consistent: pick a source and stick with it.
- Keep a record of the rate and source you used — if the ATO ever asks, "the rate on the day" is easy to defend and "I guessed" is not.
Note that the ATO has specific conversion determinations for digital currency if you accept crypto — worth reading if that applies to you. Our Australian tax invoice guide covers the invoice requirements themselves.
EU: the VAT figure must be in the national currency
Under EU VAT rules, the VAT amount on an invoice must be expressed in the member state's national currency — even when the rest of the invoice is in another currency. The conversion rate is typically the latest selling rate for the foreign currency published by the European Central Bank, or an alternative method agreed with your national tax authority. In practice:
- Invoice the client in whatever currency they prefer.
- Show the VAT amount in the national currency (EUR in eurozone countries, kronor in Sweden, etc.).
- Use the ECB rate for the relevant date, or a method your tax authority has accepted.
US: no VAT layer, but income is still reported in USD
The US has no VAT or GST, so multi-currency invoicing creates no tax-figure problem on the invoice itself. It does create one on your tax return: US freelancers report income in US dollars, so foreign-currency receipts must be converted at the spot rate on the date of the transaction, using a consistent published source. Our US sales tax guide covers when sales tax applies at all.
What to actually put on a multi-currency invoice
Whatever your country, a compliant multi-currency invoice shows:
- The invoice currency, explicitly. "USD 2,500" — never just "$2,500".
- The domestic-currency equivalents of the net, tax, and gross totals (required in the UK and EU; needed for your records everywhere else).
- The exchange rate and its date/source. A line like "Converted at the Bank of England spot rate of 1 USD = 0.75 GBP on 16 October 2026." This is what makes your conversion auditable.
- The tax treatment line matching your jurisdiction ("VAT 20% — converted to sterling as required", "GST 5% — converted to CAD per Excise Tax Act s. 159").
Our free invoice generator handles multi-currency totals, and the freelance rate calculator can fold conversion costs into your target rate.
The consistency habit that saves you at audit
Every tax authority covered here lets you choose a reasonable rate method — and every one of them punishes cherry-picking. The audit-safe routine is simple:
- Pick one rate source (your bank, the central bank, a published rate).
- Use the rate on the invoice/supply date (or your country's approved alternative).
- Print the rate and source on the invoice.
- Keep your invoice copies and the rates you used together in your records.
If you invoice in foreign currencies more than occasionally, consider doing the conversion in your accounting software rather than by hand — the bookkeeping time saved is usually worth more than any software costs. And if you're approaching a VAT/GST registration threshold, remember that foreign-currency revenue counts toward it after conversion — don't let exchange-rate noise hide a threshold crossing.
FAQ
Which exchange rate should I use for VAT/GST on a foreign-currency invoice? The rate on the date the tax becomes payable — usually the invoice date or date of supply. Use a published rate (your central bank, your bank, or an approved source) and apply it consistently. In Canada you can also use the payment date, the date you acquired the currency, or a monthly average rate, provided you stick with it.
Do I need to show the tax amount in my home currency on the invoice itself? In the UK and the EU, yes — the VAT amount must appear in the domestic currency on the invoice. In Canada and Australia, the tax must be reported in domestic currency; showing it on the invoice too is good practice and makes audits painless.
Can I just use the exchange rate my payment provider gave me? For the commercial payment, yes. For the tax calculation, only if it's a rate the tax authority accepts and you apply it consistently. Canada explicitly allows the actual conversion source; the UK and Australia accept a reasonable published rate. Don't use the rate from the day you happened to convert — use the rate from the date the tax became payable.
Do exports to foreign clients need multi-currency VAT conversion? Usually there's no VAT/GST to convert: services exported to business clients abroad are typically zero-rated or outside the scope of your domestic VAT/GST. The conversion rules matter when tax is actually chargeable — domestic clients billed in a foreign currency, EU B2C supplies under OSS, and similar cases.
What if the rate moves between the invoice date and the payment date? Use the rate for the tax calculation as of the tax point (usually the invoice date), not the payment date — unless you're in Canada and have adopted the payment-date method consistently. The difference between what you reported and what you received is a foreign exchange gain or loss for your income-tax accounting, not an adjustment to the VAT/GST.
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