Guide updated 11 July 2026
Late-payment interest on an unpaid invoice
Between companies and self-employed people, an invoice that is not paid on time accrues interest from the day after the due date, without any need for notice, and gives the right to €40 for collection costs. This is how they are calculated, with the official rate for each half-year.
The 2026 rate
Second half of 2026: 10.40% (ECB 2.40% + 8 points; Resolución de 30 de junio de 2026, BOE-A-2026-14327). First half of 2026: 10.15% (ECB 2.15% + 8; BOE-A-2025-27201). Second half of 2025: 10.15% (BOE-A-2025-13217). First half of 2025: 11.15% (BOE-A-2024-27618). Second half of 2024: 12.25% (BOE-A-2024-13089). First half of 2024: 12.50% (BOE-A-2023-26709). It is published every six months by the Secretaría General del Tesoro.
How it is calculated
Outstanding amount × rate × days late / 365, from the day after the due date. If the delay spans two half-years, each period uses its own rate: today's rate is not applied to the whole period. Example: €1,000 due on 15 May 2026 and claimed on 6 October is 46 days at 10.15% (€12.79) and 98 days at 10.40% (€27.92): €40.71 of interest, plus €40 of collection costs.
What the law says
Ley 3/2004, de lucha contra la morosidad en las operaciones comerciales, applies to payments between companies and self-employed people and with the Administration, not to consumers. The payment term is 30 days if no other is agreed and never more than 60 between companies (art. 4). Interest is owed automatically on the due date, without a demand (art. 5), at the ECB rate plus 8 points (art. 7), and the creditor also collects €40 for collection costs, without having to justify them (art. 8).
How to claim them
First, a written demand with the breakdown and a deadline to pay, sent in a way that records the date and the content (burofax with content certification or registered mail). If they do not pay, the monitorio procedure (Ley 1/2000, arts. 812 and following) allows documented money debts to be claimed; the initial petition needs neither a lawyer nor a procurador, whatever the amount (art. 814.2).
Frequently asked questions
Do they apply to an invoice to a private individual?
Not under Ley 3/2004, which covers only companies, self-employed people and the Administration. With a consumer, the legal interest rate and whatever the contract says apply.
Is interest calculated on the total including VAT?
On the amount owed, which is the one on the invoice: in practice, the total. It is the usual criterion of the courts.
Do I have to give notice first to be entitled?
No. Interest accrues by itself from the due date (art. 5). Claiming it in writing serves to put it on record and for the monitorio.