Default Interest Calculator
Get default interest under § 288 BGB from amount and dates: base rate 1.52% (since 1 July 2026) plus 5 points for consumers or 9 B2B, with a €40 flat fee.
Currently 1.52% (since 1 July 2026)
Days in Default
59 Days
Default Interest Rate
6.52 %
1.52 % + 5 pp
Default Interest
€52.70
Note: These calculations are for informational purposes only and do not replace professional tax or financial advice. All information without guarantee.
FAQ
Frequently Asked Questions
How high is the default interest rate?
For consumers, the default interest rate is 5 percentage points above the ECB base rate. For businesses (B2B), it is 9 percentage points above the base rate. The base rate is updated semi-annually.
When does default interest start?
Default interest begins when the debtor is in default, either after a payment reminder (Mahnung) or automatically 30 days after the invoice due date and receipt (for consumers, only if stated on the invoice).
Are my entered amounts stored anywhere?
No. All calculations happen exclusively in your browser. Your inputs are never sent to our server or stored. You can safely enter sensitive financial data.
Guide
What is the Default Interest Calculator?
The default interest calculator computes interest on late payments under the German Civil Code. The rate is above the Bundesbank base rate.
How does the Default Interest Calculator work?
Enter the outstanding amount, due date and payment date. The calculator computes default interest to the day. For consumers: base rate + 5 percentage points; for businesses: base rate + 9 percentage points.
Key Data and Facts
Default interest consumers: base rate + 5%. Default interest business: base rate + 9%. Base rate (since 1 Jul 2026): 1.52 %, previously 1.27 %. Flat-rate dunning costs B2B: 40 euros.
Step-by-Step Guide
How to calculate default interest step by step: 1. Enter the outstanding amount: the unpaid claim in euros. 2. Specify the due date: from when is the debtor in default? For consumers: 30 days after the due date and receipt of the invoice (Paragraph 286 BGB) or after a reminder. 3. Enter the payment date: when was actual payment made (or today's date). 4. Determine the default interest rate: consumers: base rate + 5 percentage points. Business transactions (B2B): base rate + 9 percentage points. Base rate (since 01.07.2026): 1.52 %. 5. Calculate to the exact day: default interest = amount x default interest rate x days in default / 365. 6. In the B2B area: additionally a 40 EUR reminder flat fee (Paragraph 288 Abs. 5 BGB). Example: invoice 5,000 EUR, due on 01.08.2026, payment on 15.09.2026, business transaction. Days in default: 45 days. Default interest rate: 1.52 + 9 = 10.52 %. Default interest: 5,000 x 0.1052 x 45 / 365 = 64.85 EUR. Reminder flat fee: 40 EUR. Total claim: 5,000 + 64.85 + 40 = 5,104.85 EUR.
Calculation Example
Invoice 5,000 EUR, B2B, 45 days in default from August 2026. Default interest (10.52 %): 64.85 EUR. Reminder flat fee: 40 EUR. Total claim: 5,104.85 EUR.
Sources
Official sources
Calculations are based on applicable German laws and official data:
- Deutsche Bundesbank
- Bundesanstalt für Finanzdienstleistungsaufsicht (BaFin)
- Statistisches Bundesamt (Destatis)
Full methodology at Methodology.
Reviewed by Konstantin Iakovlev · Last updated:
Finance
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