OSS return in euro: converting other currencies
You sell to customers in Poland or Sweden and receive zloty or kronor? You still file the OSS return in euro. To get there you convert at the European Central Bank (ECB) reference rate of the last day of the quarter, or the next day's if there is no rate for that day. We work through an example below.
Last updated: 29 October 2026
In brief
- Currency: The OSS return is filed in euro.
- Rate: One ECB rate per currency: the one from the last day of the quarter.
- No rate that day: Then the ECB rate of the next day applies.
In which currency do I file the OSS return?
In euro. The European Commission says the OSS return is made out in a single currency, in general euro. Only Member States that have not adopted the euro may require their national currency. For German sellers registered with the BZSt, that is the euro. The return itself is one line per country, as described in OSS return for online sellers. If the BZSt or a foreign tax office writes to you about a figure, see OSS letter from a foreign tax office or the BZSt: what to do.
What this means for you: file the OSS return in euro.
Which rate do I use for the conversion?
The law says it expressly for the OSS. Anyone using the special schemes under section 18j converts amounts in foreign currency at the rates the ECB determined for the last day of the tax period (section 16 (6) sentence 4 UStG). The OSS tax period is the calendar quarter, so the date is 31 March, 30 June, 30 September or 31 December. If no rates were determined for that day, the rates of the next day after the period apply (section 16 (6) sentence 5 UStG). For small sellers weighing the OSS, see OSS Below 10,000 Euro (Pros, Cons and Lock-in). The threshold applies only if your business is established only in Germany (§ 3c (4) UStG).
So you use neither the rate of the sale date nor the monthly average of the Federal Ministry of Finance. Those monthly average rates apply to the normal VAT advance return (section 16 (6) sentence 1 UStG), not to the OSS return.
What this means for you: convert foreign-currency amounts at the ECB rate of the last day of the quarter, not at the sale-date rate or the monthly average.
How do I work through a quarter? Example Poland and Sweden
Quarter: Q3 2026, return due 31 October 2026. The key date is 30 September 2026. The ECB reference rates of that day: 4.369 zloty per euro and 11.331 kronor per euro. The VAT rates: Poland 23%, Sweden 25% (TEDB, as of 21 October 2026). If your return is rejected, see OSS Return Rejected: Error Messages and Causes.
| Country | Net | Rate | Tax | Rate 30 Sep 2026 | Net in euro | Tax in euro |
|---|---|---|---|---|---|---|
| Poland | PLN 2,000.00 | 23% | PLN 460.00 | 4.369 | €457.77 | €105.29 |
| Sweden | SEK 3,000.00 | 25% | SEK 750.00 | 11.331 | €264.76 | €66.19 |
Total: net sales €722.53, tax €171.48. The OSS return has two lines, Poland and Sweden, each in euro. You calculate in the local currency (net times rate) and then convert the amount at the key-date rate.
Why the key date matters: had you used the rate of 28 September (4.373 zloty per euro), Poland would come to €457.35 instead of €457.77. These are small amounts, but with many orders they add up.
What this means for you: take the key-date rate, convert net and tax per country, and you get one line per country.
Where do I find the ECB rate for the end of the quarter?
The rates come from the ECB (euro foreign exchange reference rates). Note the date and the rate you used for each currency. If the ECB determined no rate for the last day of the quarter, the law uses the rate of the next day.
What this means for you: look up the ECB rate for the quarter-end date and note the date and rate for each currency.
Where are the currency and rate in my reports?
In its tax report, Amazon has columns for the transaction currency, the invoice currency, the exchange rate, the rate date and the converted amount. The documentation lists only the names. Amazon names Poland and Sweden, among others, as countries with their own shop for pan-European FBA. On eBay, the transaction report help names the columns "Transaktionswährung" and "Wechselkurs", the exchange rate eBay used when the transaction currency and the payout currency differ. That is the rate eBay converts with, not the rate for your OSS return. More: Amazon VAT report columns explained and eBay report columns explained.
What this means for you: the exchange rates in your marketplace reports are not the rate for your OSS return.
How VAT GPT helps
- Upload: You upload your Amazon and eBay reports.
- Check: VAT GPT reads the currency of each row. Amounts in the original currency and in euro are stored. You check them.
- Send: Sending the OSS return is a Pro feature.
There is Free, Go (30 days free with all Pro features) and Pro. Try for free now
Not tax advice: the content does not replace individual advice.
Frequently asked questions
Do I convert gross or net? In the local currency you first work out net and tax, then convert both amounts at the key-date rate, as in the example.
Does this apply to every foreign currency? The law speaks of amounts in foreign currency. For the OSS return the ECB rate of the key date applies.
How do I book the sales? See OSS VAT bookkeeping in Germany.