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Automatic Foreign Currency Conversion at Daily Rates with einzly

If you are self-employed in Switzerland and deal with international expenses or income in foreign currencies, you know the challenge: Which exchange rate applies? Where do I find it? How do I round correctly? einzly solves this automatically — with the current daily rate, right when you enter the transaction.

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einzly Editorial
Tax & Finance Editorial · einzly
5 min read
23 Mar 2026
Related topics
Foreign CurrencyExchange RateAccountingeinzly

01Why correct currency conversion matters

Under Swiss accounting rules, all business transactions must be recorded in the national currency CHF — even if the invoice was issued in euros, dollars, or pounds. This applies to both expenses (e.g., software subscriptions, supplier invoices) and income from international clients.

The Swiss Federal Tax Administration (ESTV) requires that foreign currency amounts be converted at the daily exchange rate or the monthly average rate. Inaccurate conversions risk corrections during tax audits — and in the worst case, additional tax payments.

ESTV RequirementThe ESTV accepts either the daily exchange rate (spot rate) or the monthly average rate for foreign currency conversions. The chosen method must be applied consistently. einzly uses the daily spot rate from the European Central Bank — a recognised and audit-proof source.

02How automatic conversion works in einzly

einzly completely eliminates the need for manual rate lookups. As soon as you enter an expense or income in a foreign currency, the following happens:

1
Select the currency

When entering an expense or income, you select the currency: EUR, USD, or GBP. The amount is entered in the original currency.

2
Daily rate is fetched automatically

einzly retrieves the current daily rate from the Frankfurter API — an open interface based on the reference rates of the European Central Bank (ECB).

3
Conversion to CHF

The foreign currency amount is converted to CHF at the daily rate. The result is rounded to 5 centimes — the Swiss standard for accounting amounts.

4
Booking in CHF

The converted CHF amount is recorded in your accounting. The original amount, currency, and exchange rate used remain traceable and stored.

The entire process takes less than a second. No manual lookups, no calculator, no rounding errors.

03Currency Converter: Try It Yourself

Try the conversion right here. This calculator uses the same data source as einzly — the current daily rate from the European Central Bank, rounded to 5 centimes.

04Where automatic conversion applies

Foreign currency conversion in einzly works everywhere amounts in a currency other than CHF are involved:

  • Expenses: Software subscriptions, hosting, supplier invoices, advertising costs — everything you pay in EUR, USD, or GBP is automatically converted to CHF.
  • Income: Payments from international clients are also recorded at the daily rate and booked in CHF.
  • Invoices: You can create invoices in EUR, USD, or GBP. Learn more in our article on creating invoices in foreign currencies.

05Comparison: Manual vs. einzly Automatic

The following table shows how much effort you save with automatic conversion:

StepManualeinzly
Look up exchange rateManually check ECB website or bankAutomatic via API
Calculate amountCalculator or ExcelInstantly calculated
Round to 5 centimesManual (error-prone)Automatically correct
Document the rateWrite down manually for auditsAutomatically stored
Time per booking2-5 minutesUnder 1 second
Error riskHigh (wrong rate, rounding)Minimal
Try einzly for freeWant to convert foreign currencies automatically? Create your free einzly account and enter your first expense in EUR, USD, or GBP — the conversion at the daily rate happens instantly.

06Frequently Asked Questions About Currency Conversion

einzly supports CHF, EUR, USD, and GBP. Expenses and income in these currencies are automatically converted to CHF at the daily exchange rate.
einzly retrieves the exchange rate from the Frankfurter API, which is based on the official reference rates of the European Central Bank (ECB). Rates are updated on every banking day.
In Switzerland, the smallest common coin value is 5 centimes (0.05 CHF). Amounts are therefore rounded to the nearest multiple of 0.05. Example: CHF 95.32 becomes CHF 95.30, and CHF 95.33 becomes CHF 95.35.
Yes. einzly automatically fills in the daily rate, but you can override the CHF amount at any time — for example, if your bank applied a different rate.
Yes. The ESTV accepts various recognised rate sources, including rates from the European Central Bank. The key requirement is that the source is applied consistently.
Invoices can be created in EUR, USD, or GBP. The conversion to CHF happens when the payment is recorded. Learn more: Invoices in foreign currencies.
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