The adjusting screw behind every default rate
Statutory default interest in Germany is always “base rate plus surcharge”. The surcharge is fixed by law: 5 percentage points where a consumer is involved, 9 percentage points for payment claims between businesses. The base rate, by contrast, moves. Anyone calculating default interest over a longer period cannot ignore it.
How the base rate is set
§ 247 BGB governs the mechanism. The starting value in the law is 3.62%. On 1 January and 1 July of each year the base rate changes by exactly as many percentage points as the so-called reference rate has risen or fallen since the last change. The reference rate is the rate of the European Central Bank's most recent main refinancing operation before the first calendar day of the half-year concerned.
So the base rate follows the central bank's key rate, but at a fixed distance and only twice a year. If the central bank changes its key rate in March, the base rate only reflects it on 1 July. Deutsche Bundesbank publishes the applicable value without delay in the Federal Gazette.
Development since 2002
The base rate in its current form has existed since 1 January 2002. Since then, roughly five phases can be distinguished:
- 2002 to 2008: the rate was between 1.13% and 3.32%. It reached its peak in the first half of 2008.
- 2009 to 2012: after the financial crisis it fell from 3.19% to 0.12% within a year and stayed almost unchanged until the end of 2012, with a brief rise to 0.37% in the second half of 2011.
- 2013 to 2022: the base rate was negative. It fell step by step to −0.88% and stayed at that value from 1 July 2016 until the end of 2022.
- 2023 and 2024: with the central bank's rate hikes it rose quickly, up to 3.62% in the first half of 2024.
- 2025 and 2026: it fell back to 1.27% and has been 1.52% since 1 July 2026.
The complete table with every half-year is shown directly below the late payment interest calculator, together with a chart of the default rates.
Negative base rate, positive default rate
A negative base rate does not mean the debtor gets money back. The surcharge is always added. At −0.88% this gave 4.12% for consumers and 8.12% between businesses. A claim of €10,000 between businesses that was in default for the whole of 2022 earned €812.00 in default interest.
Why each half-year must be calculated separately
The base rate always applies to one half-year. If a default runs over several half-years, the rate changes during the default. You therefore split the period on 1 January and 1 July and calculate each section with the rate valid there.
Example: €10,000 is in default against a consumer from 1 Jan 2024 to 31 Dec 2024; payment arrives on 1 Jan 2025.
- First half of 2024: 182 days at 8.62% (3.62% + 5) = €429.82
- Second half of 2024: 184 days at 8.37% (3.37% + 5) = €421.94
Together that is €851.76. Anyone who had used the year-end rate for the whole year would have got 10,000 · 8.37 · 366 / 36,500 = €839.29, i.e. €12.47 too little. Over longer periods and with larger amounts the differences quickly reach three digits.
Old cases: 8 instead of 9 percentage points
The 9 percentage point surcharge and the €40 flat fee only apply to obligations that arose after 28 July 2014 (Art. 229 § 34 EGBGB). For older business transactions it stays at 8 percentage points. For continuing obligations the new law applies where the consideration is provided after 30 June 2016. In the calculator, tick “Contract concluded before 29 Jul 2014”.
Keeping the base rate up to date
If you calculate default interest in your own spreadsheet, you have to add the base rate twice a year. The reliable source is the publication of Deutsche Bundesbank. The late payment interest calculator contains every value since 2002 and splits the period automatically. The calculation steps in detail are explained in the guide to late payment interest.