software-architecture.aiCalculate German default interest, exact to the day, with the current base rate
Late Payment Interest Calculator
German statutory default interest, calculated live, with the base rate straight from the Bundesbank.
The principal that is overdue, without interest.
Typically the day after the payment deadline or 30 days after the invoice was due and received.
Usually today, or the day the payment arrived.
Default interest
€64.56
91 days in default
Interest breakdown by period
| Period | Days | Base rate | Interest rate | Interest |
|---|---|---|---|---|
| 05/03/2026 – 06/30/2026 | 59 | 1.27% | 10.27% | €41.50 |
| 07/01/2026 – 08/01/2026 | 32 | 1.52% | 10.52% | €23.06 |
The base rate since 2002
Your default period is highlighted. Hover over the chart to see the rate at any point in time.
Bundesbank service not reachable, using bundled history as of 08/01/2026 · current base rate: 1.52%
How the calculation works
The formula is: amount times interest rate times days in default, divided by the days in the year. Because the base rate changes on 1 January and 1 July, a longer default period consists of several segments with different rates. The calculator splits these automatically, counts days exactly, and uses 365 or 366 days depending on the calendar year. Compound interest is not allowed (Sec. 289 BGB) and is not applied. Note: the official German court order procedure partly calculates with a 360-day banking year, which yields slightly different results. This calculator uses exact calendar days, the method common for civil claims.
5 or 9 percentage points?
If your debtor is a consumer, you can claim the base rate plus 5 percentage points (Sec. 288 (1) BGB). If both sides act commercially and the claim is a payment claim, it is base rate plus 9 percentage points (Sec. 288 (2) BGB). Businesses can additionally claim a flat 40 euros per late payment (Sec. 288 (5) BGB). A higher contractual interest rate remains unaffected: the statutory rate is the minimum you can claim without any agreement.
This calculator provides no legal advice and no guarantee for individual cases. Basis: Sec. 247, 288, 289 German Civil Code and the base rate as published by the Deutsche Bundesbank.
Frequently asked questions
- How is default interest calculated?
- Amount times interest rate times days in default, divided by the days in the year (365 or 366). The rate is the base rate under Sec. 247 BGB plus 5 percentage points for consumer transactions or plus 9 percentage points for commercial debts. The base rate changes on 1 January and 1 July, so longer periods are split into segments. That is exactly what this calculator handles for you.
- Where does the current base rate come from?
- Directly from the Deutsche Bundesbank data service, which publishes the rate under Sec. 247 BGB, including the full history since 2002. The data refreshes daily, and the load date is shown below the chart.
- What is the 40 euro flat fee?
- If the debtor is not a consumer, Sec. 288 (5) BGB grants a flat 40 euro compensation per late payment on top of the interest. It is credited against further recovery costs such as legal fees. Many businesses simply do not know they are entitled to it.
- When does default begin?
- Typically after a reminder, on the day after a contractual payment deadline, or at the latest 30 days after the invoice was due and received. For consumers the 30-day rule only applies if the invoice explicitly mentioned it.
- Can the base rate be negative?
- Yes. Between 2013 and 2022 it was below zero, at times minus 0.88 percent. The 5 or 9 percentage point surcharge is added on top, so default interest stayed clearly positive even then.
Built at the workbench
This was the small part.
This tool went from market analysis to finished page in an afternoon: a tested calculation core, live data from the Bundesbank, done. I build exactly this kind of tool for the workflows that eat time in your business.