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Invoice overdue: what you may claim from a business customer

Von Johanna Brecht, Redakteurin für Verbraucherfinanzen · 9.9.2026 · 10 Min. Lesezeit

The invoice left your office at the end of May. 4,800 euro, payable by 31 May. It is now September. The customer has not disappeared. He even gets in touch, friendly about it, pointing to his own cash position and asking for a little patience. You give him the patience, because you would like the same contract again next year.

What has built up over those hundred days is something very few firms ever work out. It is 137.36 euro in interest and a flat sum of 40 euro, 177.36 euro together, and you did not have to lift a finger to earn any of it. The claim arises on its own, straight out of the statute – no clause, no agreement, no reminder. It disappears only if you never put it on paper.

Between businesses that is not small change measured against the effort. It is one sentence in a letter you are sending anyway.

Nine percentage points, not five

The rate for late payment sits in Section 288 of the German Civil Code (BGB), and it is not the same for every debtor. Subsection 1 names five percentage points above the base rate. That is the figure almost everyone knows, and the one plenty of firms wrongly apply to their business customers as well.

Subsection 2 is the one that matters to you. For payment claims in which no consumer is involved, the rate is nine percentage points above the base rate. Very nearly double.

The base rate itself is not a market price you have to look up daily. The Deutsche Bundesbank sets it afresh twice a year, on 1 January and on 1 July (Section 247 BGB). Since 1 July 2026 it has stood at 1.52 per cent. That gives you two rates, and only one of them belongs in a letter to a company:

Ten and a half per cent a year is more than most overdraft facilities cost. Leave a receivable standing for months and you are, in substance, lending your customer money at a rate you would be glad to earn yourself, and then declining to bill him for it.

One point about accuracy. If the period of default runs across a 1 January or a 1 July, each stretch carries the base rate that applied at the time. A single blended rate across the whole period would be wrong. In the example above, thirty days fall in the period with a base rate of 1.27 per cent and seventy days in the period with 1.52 per cent.

The 40 euro nobody can negotiate away

Section 288(5) BGB hands you a flat sum of 40 euro on top of the interest. It applies only where the debtor is not a consumer – against private customers you may never charge it.

The flat sum arises per payment claim. If three invoices to the same customer are outstanding, it arises three times over. Where a single contract provides for several instalment payments on account, the Federal Court of Justice has taken a different view, and there it falls due only once.

Subsection 6 deserves a slow read. An agreement made in advance that excludes the claim to default interest is void. And where the exclusion covers the 40 euro flat sum, the statute expressly presumes that such a clause is grossly unfair. So when the purchasing terms of a large customer state that late payment flat sums do not apply, that sentence does not stop you. The clause does not hold.

There is one catch, and it is rarely mentioned. Under subsection 5 sentence 3, the flat sum has to be set off against damages to the extent that those damages consist of the costs of pursuing the claim. Hand the file to a lawyer later on and the flat sum reduces his recoverable costs; it does not sit on top of them. Until that day it is still money that belongs to you.

When the clock actually starts

The commonest mistake in a late payment claim is the starting date. Interest does not run from the date on the invoice. It runs from default, and Section 286 BGB knows three routes into it:

• A payment date fixed by the calendar. If the invoice says "payable by 31 May", or the contract names a date, default begins the day after, with no reminder needed at all (Section 286(2) no. 1 BGB). "Payable within 14 days" does the same job, because the date can be worked out.
• A reminder. Without a fixed date you need a reminder, and default starts on the day after it reaches the customer (Section 286(1) BGB).
• The 30-day rule. At the latest, default sets in 30 days after the invoice has fallen due and arrived (Section 286(3) BGB). Against consumers that only works if the invoice pointed the rule out. Against companies no such note is required.

The third route is your safety net. Even if you never sent a reminder and never set a date, your business customer is in default thirty days after the invoice reached him. Which means the answer to "we never agreed any interest" is simple – nobody has to agree it.

Step by step to the claim

1. Fix the starting date. Which of the three routes applies in your case? Write down the first day of default and keep whatever proves it.
2. Calculate the interest by the day. Gross amount times rate times days, divided by 365. On the gross amount, because what the customer owes is the invoice including VAT.
3. Respect the base rate cut-off dates. If the default period runs across 1 January or 1 July, calculate each stretch separately and show both lines.
4. Add 40 euro per outstanding invoice. Only where the debtor is a business, and only once per contract where the invoices are instalments on account.
5. Put a number on it in writing. Not "plus statutory default interest", but the actual amount, with the period it covers and the section it rests on. Quantified claims get paid. General references get filed.
6. Set a deadline. A specific date. Not a formula such as "without delay", which nobody has ever treated as a date.
7. Decide what happens if nothing comes back. A court payment order, a lawyer, or an instalment agreement. The one thing that does not help is waiting longer, because the standard limitation period is three years, running to the end of the year.

What your customer will say

Three sentences come back again and again, and each of them can be answered in a line.

"We pay on 60 days as a matter of policy." Section 271a(1) BGB lets a payment term longer than 60 days stand between businesses only where the parties expressly agreed it and it is not grossly unfair. If your customer is a public authority, anything beyond 60 days is void from the outset, and anything beyond 30 days needs an objective justification (subsection 2). A term dropped unilaterally into an order confirmation is not an agreement.

"Our purchasing terms exclude late payment flat sums." That clause does not hold. See above, Section 288(6) BGB.

"We never received the invoice." This is the only objection with any substance, because the 30-day rule depends on the invoice having arrived. Which is exactly why it pays to keep your invoice dispatch traceable. A send log from your invoicing system is normally enough.

When numbers alone do not help: the court payment order

At some point the friendly letter is exhausted. The next step is the German court dunning procedure, which produces a Mahnbescheid ("court payment order"), and it is a good deal less laborious than its reputation suggests. The application runs online through the court responsible for payment orders, and you do not need a lawyer to file it.

The court fee is half a fee unit under the Court Costs Act (Gerichtskostengesetz), but at least 36 euro. Those costs form part of the loss caused by the default, so where the claim is justified your customer carries them in the end. If he objects within two weeks, the matter moves into ordinary proceedings and further costs follow.

More important than the money is what the step does to the clock. The standard limitation period is three years and runs to the end of the year in which the claim arose. An invoice from 2026 therefore becomes time-barred at the end of 31 December 2029. A court payment order suspends that limitation period. A reminder does not, however many of them you send.

Why this touches your own credit standing

There is a second reason to pursue open receivables properly, and it has nothing to do with the 177 euro. Money that does not come in does not go out either. A company that starts paying its own suppliers late is the one they report next, and those entries land in its own file. Payment behaviour carries 25 per cent there, the heaviest single item in Creditreform's Bonitätsindex, the German business credit index that a supplier reads before setting your terms.

A chain of three slow-paying customers can end up costing you your own grade. It is the quietest way there is for somebody else's late payment to turn into worse terms for you.

What FIAON takes on

FIAON does not collect debts from your customers. What FIAON does begins on the other side of the ledger: obtaining the company file and the owner's personal credit file, explaining every entry in them, challenging entries that should never have been reported, and tracking the deadlines that follow, so that your customers' payment problems do not end up recorded against you. If a company card is supposed to carry you across the hole a late payer leaves behind, FIAON puts that application together. Whether the card comes at all, and with what limit, is the issuer's decision alone.

What does not work

Where a claim is disputed, the customer does not simply fall into default. A customer who seriously challenges the work owes no default interest for the time being, and that is only settled once the claim is established in principle. Sending him a quantified interest calculation will not change the position.

Interest is also no substitute for enforcement. A customer who cannot pay will not pay 10.52 per cent either. The late payment claim is leverage against somebody who could pay and has chosen not to, and a useful argument when you negotiate an instalment agreement. It is not a replacement for a court payment order.

And a rate higher than the statutory one is yours only where it has been agreed in the contract, or where you can prove a specific higher loss, an overdraft that actually costs you more, for instance (Section 288(3) BGB).

The three sentences that matter

Between businesses the statutory rate for late payment is nine percentage points above the base rate, so 10.52 per cent since 1 July 2026, plus 40 euro for every outstanding invoice. The claim arises without you doing anything, but it gets paid only if you put a figure on it. And because a quarter of your own credit grade rests on how you pay, chasing other people's invoices is upkeep of your own file at the same time.