Free online tool
Late-payment interest calculator
Late-payment interest and the flat fee for Austria and Germany, to the day, at the statutory rate.
- No account
- Nothing is stored
- Splits at 1 January and 1 July
Base rates
The rates the calculator uses
Both countries publish their own base rate, and the margin on top is set by law. The calculator takes the rate for each half-year from this table (as of 07/10/2026).
Germany · Deutsche Bundesbank
| Half-year from | Base rate | Business client | Consumer involved |
|---|---|---|---|
| 01/07/2026 | 1.52 % | 10.52 % | 6.52 % |
| 01/01/2026 | 1.27 % | 10.27 % | 6.27 % |
| 01/07/2025 | 1.27 % | 10.27 % | 6.27 % |
| 01/01/2025 | 2.27 % | 11.27 % | 7.27 % |
§ 288 (2) / (1) BGB: +9 / +5.
Austria · OeNB, value on 1 January / 1 July
| Half-year from | Base rate | Business client | Consumer involved |
|---|---|---|---|
| 01/07/2026 | 1.53 % | 10.73 % | 4.00 % |
| 01/01/2026 | 1.53 % | 10.73 % | 4.00 % |
| 01/07/2025 | 1.53 % | 10.73 % | 4.00 % |
| 01/01/2025 | 2.53 % | 11.73 % | 4.00 % |
§ 456 UGB: +9.2 · Consumer involved in Austria: always 4 % (§ 1000 (1) ABGB).
The OeNB base rate has been 2.03 % since 16/09/2026. For late-payment interest, though, § 456 UGB uses the value on 1 January or 1 July for the whole half-year: 1.53 % until 31/12/2026 (10.73 % between businesses). If nothing changes before then, it will be 2.03 % + 9.2 = 11.23 % from 01/01/2027.
How it’s calculated
Amount, rate, days
Interest = amount outstanding × rate × days in default ÷ 365
The rate is a margin on top of the base rate: in Germany 9 percentage points between businesses and 5 with a consumer, in Austria 9.2 percentage points between businesses. With private clients, Austria uses a fixed 4 %. The base rates are published by the Deutsche Bundesbank and the Oesterreichische Nationalbank. In Germany the base rate changes on 1 January and 1 July; in Austria, late-payment interest uses the base rate on 1 January or 1 July for the whole half-year (§ 456 UGB). The €40 flat fee only applies if your client is a business.
If the period runs past 1 January or 1 July, the calculator splits it and uses each half-year’s rate. Each line is rounded to the cent.
The calculator assumes your client is in default from the day after the payment date. When exactly that holds is explained in the guide Late-payment interest.
Sources
- § 247 BGB
- § 286 BGB
- § 288 BGB
- § 456 UGB
- § 458 UGB
- § 1000 ABGB
- § 6a KSchG
- Base rates: Deutsche Bundesbank (Basiszinssatz, § 247 BGB) and Oesterreichische Nationalbank (Basis- und Referenzzinssätze).
Frequently asked questions
Which rate applies to my invoice?
It depends on the country and the client. Currently: Germany 10.52 % between businesses and 6.52 % with a consumer (§ 288 BGB), Austria 10.73 % between businesses (§ 456 UGB) and 4 % otherwise (§ 1000 (1) ABGB).
From when can I charge late-payment interest?
From default. In Austria, as soon as the money isn’t in your account by the payment date; private clients only have to order the transfer on the due date (§ 6a (2) KSchG). In Germany with the first reminder after the due date, without a reminder if a date was agreed, otherwise at the latest 30 days after the due date and receipt of the invoice.
Do I always get the €40 flat fee?
Only with business clients, once per claim (§ 288 (5) BGB, § 458 UGB). There is no flat fee with private clients.
What if the client paid only part of it?
Enter the amount still outstanding. For the period before the part payment, run a separate calculation: with the amount outstanding then and the day of the part payment as "Paid on".
Why does Austria still use the old base rate?
Because § 456 UGB takes the base rate on 1 January or 1 July for the whole half-year. The OeNB rate rose to 2.03 % on 16/09/2026, but late-payment interest stays at 10.73 % between businesses until 31/12/2026.
Let Backbone follow up for you
Reminders, notices, interest: set it up once and it runs. Free for 7 days.
7 days free, card required. €0.00 due today.
How Backbone chases payments for you
- The payment reminder, 1st and 2nd notice go out on your schedule, with your wording.
- Backbone calculates late-payment interest by country and client type, and adds the flat fee for business clients only.
- Invoice disputed? Pause reminders for just that invoice.
Further reading
Not tax or legal advice. The calculator shows the statutory interest rate; whether and from when your client is in default depends on the individual case.
Checked on 07/10/2026 against § 247, § 286, § 288 BGB, § 456, § 458 UGB, § 1000 ABGB, § 6a KSchG; base rates from Deutsche Bundesbank and OeNB.