Invoicing in a foreign currency in Germany: which exchange rate applies? (ECB, DATEV, OSS)

Can I invoice in a foreign currency?

Yes. Your invoice may be issued entirely in CHF, USD, GBP or another currency. The condition is in the EU VAT Directive: the VAT must be stated in the currency of the member state where the sale takes place (Art. 230 of the VAT Directive, German version). For a German sale, that means the VAT amount must also appear in euros on the invoice. The German VAT Act (UStG) does not repeat this requirement explicitly; the conversion follows § 16(6) UStG (German).

Rechnungskit handles exactly that for you. Invoices can be issued in EUR and in CHF, USD, GBP, SEK, DKK, NOK, PLN, CZK and CAD, and the EUR VAT amount is added automatically.

Which rate applies?

Rechnungskit converts at the ECB reference rate, the fixing the European Central Bank publishes every day. For the EUR amount on the invoice, it uses the last rate published on the issue date.

The rate is not fetched again each time the invoice is opened. It is frozen when the invoice is issued, and the rate, rate date and rate source become a fixed part of the document. If the customer pays weeks later at a different rate, the document stays as it is. For VAT purposes, exchange rate changes between the supply and the receipt of payment are disregarded (section 16.4(1) sentence 2 UStAE, German).

In the e-invoice (BT-6/BT-111)

For a foreign currency invoice, the e-invoice (ZUGFeRD 2.5 / EN 16931) uses separate currency fields:

• BT-5, invoice currency: the actual currency of the document (for example USD).
• BT-6, VAT accounting currency: EUR, because German VAT has to be stated in euros.
• BT-111, VAT total in accounting currency: the EUR amount calculated at the ECB rate.

This is the structure the standard provides for documents whose VAT currency differs from the invoice currency. The invoice stays correct as machine-readable data and passes format validation.

DATEV: rate and EUR base

DATEV is the accounting software most German tax advisors use, and the DATEV export is how your bookings reach them. In the export, every foreign currency booking carries the full conversion:

Your tax advisor can follow the conversion without gaps and, if needed, switch to the official monthly rate without missing any information.

OSS: the quarter-end rate

If you sell to consumers in the EU and report through the OSS scheme (One-Stop Shop, the EU-wide VAT return for cross-border B2C sales), a stricter rule fixed by law applies. OSS sales in a foreign currency are converted at the ECB rate of the last day of the reporting quarter; if there is no rate for that day, the next day's rate applies (§ 16(6) sentences 4 and 5 UStG, German). The tax authorities explicitly rule out a monthly average rate here (section 18j.1(4) UStAE, German), and the law does not provide for your payment provider's rates either.

Rechnungskit applies exactly this quarter-end rate. While the quarter is still running, the preview shows a provisional rate, and the return can only be locked once the final quarter rate is available. The rate used is documented in the locked return.

ECB daily rate or BMF monthly rate?

One point to keep in mind: which rate you may use for the tax is governed by § 16(6) UStG (German), not by § 14 UStG. The daily rate on the invoice is therefore not automatically the rate you use when you file the tax.

For the VAT pre-return (Umsatzsteuer-Voranmeldung), the legal default is the monthly average rate that the BMF publishes for the month of the supply (§ 16(6) sentence 1 UStG, German). You may only use a daily rate, such as the ECB reference rate, if your tax office permits it (§ 16(6) sentence 3 UStG, German). As a simplification, the tax office can also permit you to use the average rate of the previous month consistently, which is already known when you invoice (section 16.4(2) UStAE, German).

Rechnungskit supports both methods, with the ECB daily rate as the default. Without permission, that rate is not the legal standard for the pre-return, so your tax advisor converts to the monthly rate. If you have permission for the prior-month rate, go to Settings → DATEV and switch to the BMF prior-month rate with one click, confirming that you have the permission. From then on, Rechnungskit uses the previous month's average rate. The BMF monthly rates are synced automatically and rounded to four decimal places, so the value matches the officially published rate. Which method applies to you is something to settle with your tax advisor; the DATEV export provides the basis (rate, EUR base and rate date for each booking).

OSS is unaffected: the law prescribes the quarter-end rate there, and Rechnungskit applies it directly, whichever method you chose for invoices. More under foreign currencies in detail.

How it works in Rechnungskit

You do not have to convert anything or maintain a rate table:

1. Rates sync automatically. Rechnungskit syncs the ECB reference rates daily and keeps the history, so the correct daily rate is available for older documents too.
2. The document is created in the order currency. An order in USD becomes an invoice in USD, with the VAT amount in EUR calculated at the ECB rate of the issue date and frozen.
3. The export is ready. DATEV gets the rate and the EUR base, and OSS converts automatically at the quarter-end rate. Your tax advisor decides on the final rate method.

Payments in an unsupported currency (for example JPY), or in a currency that does not match the order, are never invoiced automatically. They become a task to resolve, so no document is created with a questionable rate.

Read more about the EU scheme under OSS return and about the tamper-proof export under DATEV export.