Late Payment Interest Calculator
Calculate late payment interest per § 288 BGB for consumers or B2B using the commercial interest method, quickly and transparently. GDPR-compliant.
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Legal notice
Current as of: 11.08.2026.
The results reflect the legal and fiscal state as of the date stated above. They are provided for general information and initial guidance only. They are not individual financial, tax or legal advice, and no guarantee is given as to their accuracy, completeness or suitability for your circumstances. In particular, the results are not a substitute for an official or judicial assessment. Please check the information independently and seek qualified advice where appropriate, as you are solely responsible for any decision made in reliance on the result.
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Calculate late payment interest per sec. 288 BGB
When an invoice is not paid on time, the debtor is in default, in most cases once a reminder arrives or a set payment deadline has passed. From that point on, the creditor may claim late payment interest. This calculator works out the interest per sec. 288 of the German Civil Code (BGB) from the amount owing, the days in default and the current base rate of the German Bundesbank, using the commercial interest method (days divided by 360).
Which surcharge applies?
- Consumer: 5 percentage points above the base rate.
- Business (B2B): 9 percentage points above the base rate.
The difference is set by statute: a lower surcharge applies against consumers, a higher one between businesses. The German base rate is published by the Bundesbank under sec. 247 BGB and revised twice a year (on 1 January and 1 July). You enter the rate that is valid at the time of your calculation; an example value is prefilled as a guide. Because the figures can change, please check the current value against an official source.
This tool provides a guide value for orientation and is not legal advice. The statutory rate is a minimum claim, so if your case is uncertain, consult a lawyer.
Frequently asked questions
How is late payment interest calculated?
Usually by the commercial interest method: amount × rate × days divided by 360.
Are my inputs stored?
No. Everything runs locally in your browser; nothing is transmitted or stored.
Read more about this tool
How does the calculator work?
The tool needs four inputs: the outstanding amount, the date default begins, the date of payment and the valid German base rate. From the two dates it works out the number of days in default. The interest rate is the base rate plus the right surcharge: 5 percentage points for consumers, 9 percentage points between businesses. Interest itself is calculated with the commercial method, that is amount times rate in percent times days divided by 360.
The calculator also shows the effective annual rate, so you can see at a glance which rate your claim is based on. It also gives the daily interest, so you can see how much accrues on every single day of delay. You can change the base rate any time and read off the effect on the result immediately.
The legal background to sec. 288 BGB
The statutory late payment interest is laid down in sec. 288 BGB and applies once the debtor is in default. Default itself follows from sec. 286 BGB: it normally occurs after a reminder (Mahnung) or the expiry of an agreed deadline. The base rate is published by the German Bundesbank under sec. 247 BGB on 1 January and 1 July each year.
In practice this means that when a fixed payment date is agreed, a reminder is often not needed at all: the debtor is automatically in default once the deadline has passed. If no date was agreed, the creditor normally has to send a reminder. Between businesses, sec. 286 (3) BGB provides that default arises without any further reminder once a certain time has passed since the invoice was received, at the latest after 30 days.
The statutory rate is a minimum claim; a higher contractually agreed rate takes precedence. In business to business cases a flat damage allowance of 40 euros per claim may additionally be claimed under sec. 288 (5) BGB. The calculator only shows the interest, not this allowance. The rates and rules can change, so verify the current position against an official source such as gesetze-im-internet.de before you assert a claim.
Does the calculation run locally?
Yes. The late payment interest calculator runs 100 % locally in your browser. Your inputs are neither sent to a server nor stored; they never leave your device. You can safely try different amounts and dates and compare the outcomes.