What is the German base rate in 2026?

The base rate (Basiszinssatz) is fixed twice a year by the Deutsche Bundesbank — on 1 January and 1 July. Look up the current figure at bundesbank.de → Statistik → Geld- und Kapitalmärkte → Basiszinssatz. Because it changes, check before each calculation. The rate applicable on the day default set in is the rate that applies — long default periods spanning a rate change are split into sub-periods.

Can I claim default interest without first sending a Mahnung?

Yes, in two situations. First: when the invoice carries a calendar-fixed due date — a specific date, not just **payable within 14 days** — default sets in under § 286 (2) No. 1 BGB without a Mahnung when that date passes. Second, and particularly important in B2B: under § 286 (3) BGB default sets in at the latest 30 days after the debtor receives the due invoice — also without a Mahnung. The 30-day rule is the most overlooked in practice.

Is default interest subject to VAT?

No. Default interest is treated as damages and therefore not subject to VAT (no exchange of services under § 1 (1) UStG). It is, however, operating income and therefore taxable for income / corporate-tax purposes. Book it net to an account such as **Interest income** or **Income from receivables**. The same applies to the €40 flat fee and to dunning fees.

What happens if the debtor makes a partial payment after default starts?

A partial payment does not end default — it reduces the interest base for the remaining default period. Absent a different agreement, § 367 BGB applies: the partial payment is set off first against costs (dunning fees, flat fee), then interest, then the principal. Because of this ordering, the principal only shrinks once all ancillary claims are covered — the standard case in default, which works against the debtor.

Can I claim the €40 flat fee from consumer debtors as well?

No. § 288 (5) BGB expressly limits the flat-fee claim to commercial-to-commercial dealings. For B2C receivables only regular default interest (base rate + 5 pp) and, from the second Mahnung onward, dunning fees can be claimed. Analogous extensions to consumers routinely fail in court.

How far back can I claim default interest?

Default interest is time-barred together with the underlying principal — three years from the end of the calendar year in which the claim arose (§§ 195, 199 BGB). An invoice that became due in January 2026 is therefore time-barred at the end of 31 December 2029. Accruing default interest expires alongside. Check the limitation period before back-claiming interest on old receivables — otherwise the debtor's limitation defence cuts the claim cleanly.

Reference

Calculating German default interest in 2026: base rate, formula, B2B and B2C worked examples

Kyle Nelson20 June 2026

German default interest is governed by § 288 BGB. For B2B receivables the rate is the Bundesbank base rate plus 9 percentage points; for B2C it's base rate plus 5. This reference walks through the formula, where to look up the current base rate, four fully worked examples, the additional €40 statutory flat fee under § 288 (5) BGB, and the case-law boundaries on when courts allow add-on collection costs.

What default interest is — and when it starts running

Default interest (Verzugszinsen) is the statutory damages payment for late payment of a due monetary claim. It accrues from the day the debtor enters default until the day before actual payment — and it is a legal entitlement, not a negotiable line item.

When default sets in is governed by § 286 BGB. Three triggers cover almost every receivable in practice:

On receipt of a Mahnung after the invoice has become due. The classic case — the Mahnung is the instrument that triggers default.
Automatically with a calendar-fixed due date. When the invoice carries a specific date (e.g. payable by 14 July 2026), default sets in under § 286 (2) No. 1 BGB without any Mahnung when that date passes.
For B2B claims, at the latest 30 days after the debtor receives the invoice and it becomes due (§ 286 (3) BGB) — without a Mahnung, without a calendar-fixed date. This is the single most overlooked rule in German B2B commerce.

The base rate (Basiszinssatz): what it is and where to find it

The Basiszinssatz is a reference rate fixed twice a year by the Deutsche Bundesbank, anchored to the ECB main refinancing rate. The Bundesbank publishes the value on 1 January and 1 July of each year.

The current value lives at bundesbank.de → Statistik → Geld- und Kapitalmärkte → Basiszinssatz. Through the low-rate years the figure was negative — down to -0.88 %. Following the ECB's 2022 turn it has climbed back into positive single-digit territory and sits there in 2026.

For the calculation always use the base rate that applied on the day default set in, even if the figure later changes. If the base rate updates mid-period, split the calculation into two sub-periods.

The formula: calculating default interest for B2B and B2C

§ 288 BGB distinguishes two rates depending on whether the debtor is a consumer or a commercial entity:

Debtor type	Default rate	Legal basis	Additional flat fee
Consumer (B2C)	Base rate + 5 pp	§ 288 (1) BGB	None
Commercial (B2B)	Base rate + 9 pp	§ 288 (2) BGB	€40.00 (§ 288 (5) BGB)

Debtor typeConsumer (B2C)

Default rateBase rate + 5 pp

Legal basis§ 288 (1) BGB

Additional flat feeNone

Debtor typeCommercial (B2B)

Default rateBase rate + 9 pp

Legal basis§ 288 (2) BGB

Additional flat fee€40.00 (§ 288 (5) BGB)

Formula and application

The formula is the same for both — only the rate differs:

Default interest = receivable × default rate × days in default / 365

Three application notes:

The default rate is the base rate plus 5 (B2C) or 9 (B2B) percentage points — added, not multiplied.
Days in default are counted from the day default began (inclusive) to the day before actual payment (exclusive).
Leap years are conventionally treated as 365 days for this purpose — using 366 is not wrong but uncommon and invites pushback.

Four worked examples

Every example uses an assumed base rate of 3.12 % — always pull the current value from bundesbank.de before a real Mahnung.

Example 1 — B2B invoice, short default. Invoice EUR 1,200.00, 14 days in default. Default rate: 3.12 % + 9 % = 12.12 %. Default interest = 1,200 × 12.12 % × 14 / 365 = EUR 5.58. Plus the EUR 40.00 flat fee. Total addition: EUR 45.58.

Example 2 — B2B invoice, long default. Invoice EUR 8,500.00, 90 days in default. Default interest = 8,500 × 12.12 % × 90 / 365 = EUR 253.93. Plus EUR 40.00 flat fee. Total: EUR 293.93.

Example 3 — B2C invoice, medium default. Invoice EUR 480.00 (think a tradesman's invoice to a private customer), 45 days in default. B2C default rate: 3.12 % + 5 % = 8.12 %. Default interest = 480 × 8.12 % × 45 / 365 = EUR 4.80. No EUR 40 flat fee for B2C. Total addition: EUR 4.80.

Example 4 — B2B invoice straddling a base-rate change. Invoice EUR 5,000.00, default from 1 May 2026, payment received 30 September 2026. Base rate through 30 June: 3.12 %. Base rate from 1 July: assume 3.40 %. May–June days: 61 at rate 12.12 %. July–September days: 91 at rate 12.40 %. Tranche 1: 5,000 × 12.12 % × 61 / 365 = EUR 101.25. Tranche 2: 5,000 × 12.40 % × 91 / 365 = EUR 154.52. Sum: EUR 255.77 plus EUR 40.00 flat fee = EUR 295.77.

The €40 statutory flat fee under § 288 (5) BGB

For B2B receivables the defaulting commercial debtor additionally owes the creditor a flat compensation of EUR 40.00 — independent of actual damages, independent of receivable size, independent of how long default has lasted.

Three points routinely misunderstood:

The flat fee applies once per receivable — not per Mahnung. Three Mahnungen on the same invoice trigger one EUR 40 fee, not three.
It is set off against any later claim for collection-agency or legal fees, but is not lost. If the later claim is smaller, the excess of the flat fee remains.
No equivalent for B2C. § 288 (5) BGB expressly limits the claim to commercial-to-commercial dealings. Attempts to apply it by analogy to consumers fail in court.

Dunning fees vs. default interest — the most common confusion

Dunning fees and default interest are two separate claims on two separate legal bases. To claim both correctly you have to keep them apart.

Default interest (§ 288 BGB) compensates the creditor's liquidity damage — running continuously, expressed as a percentage of the receivable per year.

Dunning fees reimburse the creditor's actual processing cost (§§ 280, 286 BGB). They fall as a flat amount per Mahnung — German courts accept EUR 2.50 to EUR 5.00 per Mahnung without itemised proof.

The €40 flat fee under § 288 (5) BGB is conceptually closer to dunning fees — damages for handling effort — but it becomes due automatically with default, not per Mahnung. It is set off against dunning fees if both are claimed.

A complete default-claim breakdown therefore has four line items: principal, default interest, dunning fees (from the second Mahnung onward), €40 flat fee (B2B only).

When courts cut default interest

The maths of default interest itself is rarely the disputed point — it's just arithmetic. Where courts intervene, it's usually one of three things:

Dispute over when default began. If the debtor contests receipt of the Mahnung, or argues the due date wasn't unambiguously fixed, the court can move the default start later. Practical effect: fewer default days, lower interest.

Dispute over the principal amount. Default interest is only owed on the principal the court finds owing. If part of the invoice was rightfully contested (defective performance, scope dispute), the interest base shrinks with it.

Collection-agency fees above the flat fee. Here it gets technical: BGH case law allows reimbursement only when the agency was instructed *after* default set in *and* the debtor was not obviously insolvent or refusing to pay. Engage an agency too early or too obviously hopelessly, and you eat the cost yourself.

Letting software calculate the interest

Mathematically trivial, operationally not: look up the current base rate, count default days precisely, split into sub-periods at base-rate changes, separate the flat fee, transcribe the result into the Mahnung. That's five to ten minutes per Mahnung.

Modern receivables software handles it automatically: the current base rate is fetched via API, default days are counted to the day from the default trigger, B2B vs. B2C differentiation runs off the stored debtor type, the EUR 40 flat fee appears automatically on B2B debtors — and all values land in the Mahnung in the debtor's language.

kvit does this from the second Mahnung onward without further input. The dashboard shows calculated default interest and the flat fee as separate line items — auditable if you want, invisible if you don't.

Three steps to a correct default-interest claim

Pragmatic workflow that survives court scrutiny and avoids the most common arithmetic mistakes.

Establish when default beganCheck in sequence: does the invoice carry a calendar-fixed due date? If not: was a Mahnung sent with documented receipt? If neither, and the debtor is commercial: 30 days after invoice receipt and due date? The earliest of these is the default start.
Capture base rate and daysPull the current base rate from bundesbank.de. Count default days — from the trigger day (inclusive) to the day before payment (exclusive). If the base rate changed mid-period, split into two sub-periods.
Itemise interest and flat fee separatelyIn the Mahnung or claim breakdown: principal, default interest (B2B: + 9 pp, B2C: + 5 pp), dunning fee from the second Mahnung (EUR 2.50–5.00), EUR 40 flat fee (B2B only, once per receivable). Four separate lines, cleanly calculated — never lumped together.

Frequently asked questions

What is the German base rate in 2026?: The base rate (Basiszinssatz) is fixed twice a year by the Deutsche Bundesbank — on 1 January and 1 July. Look up the current figure at bundesbank.de → Statistik → Geld- und Kapitalmärkte → Basiszinssatz. Because it changes, check before each calculation. The rate applicable on the day default set in is the rate that applies — long default periods spanning a rate change are split into sub-periods.
Can I claim default interest without first sending a Mahnung?: Yes, in two situations. First: when the invoice carries a calendar-fixed due date — a specific date, not just payable within 14 days — default sets in under § 286 (2) No. 1 BGB without a Mahnung when that date passes. Second, and particularly important in B2B: under § 286 (3) BGB default sets in at the latest 30 days after the debtor receives the due invoice — also without a Mahnung. The 30-day rule is the most overlooked in practice.
Is default interest subject to VAT?: No. Default interest is treated as damages and therefore not subject to VAT (no exchange of services under § 1 (1) UStG). It is, however, operating income and therefore taxable for income / corporate-tax purposes. Book it net to an account such as Interest income or Income from receivables. The same applies to the €40 flat fee and to dunning fees.
What happens if the debtor makes a partial payment after default starts?: A partial payment does not end default — it reduces the interest base for the remaining default period. Absent a different agreement, § 367 BGB applies: the partial payment is set off first against costs (dunning fees, flat fee), then interest, then the principal. Because of this ordering, the principal only shrinks once all ancillary claims are covered — the standard case in default, which works against the debtor.
Can I claim the €40 flat fee from consumer debtors as well?: No. § 288 (5) BGB expressly limits the flat-fee claim to commercial-to-commercial dealings. For B2C receivables only regular default interest (base rate + 5 pp) and, from the second Mahnung onward, dunning fees can be claimed. Analogous extensions to consumers routinely fail in court.
How far back can I claim default interest?: Default interest is time-barred together with the underlying principal — three years from the end of the calendar year in which the claim arose (§§ 195, 199 BGB). An invoice that became due in January 2026 is therefore time-barred at the end of 31 December 2029. Accruing default interest expires alongside. Check the limitation period before back-claiming interest on old receivables — otherwise the debtor's limitation defence cuts the claim cleanly.

Default interest that calculates itself

kvit calculates default interest, dunning fees and the €40 flat fee automatically — current base rate, B2B/B2C differentiation, to the day from default trigger. Direct into the Mahnung, in the debtor's language, from EUR 0 per month.

Try kvit free