When am I entitled to claim late payment interest?

You are entitled from the day after the agreed payment deadline expires (or the statutory 30-day deadline if none was agreed), provided you have fulfilled your obligations: delivering the goods or providing the service.

What is the commercial late payment interest rate in Spain in 2026?

The rate for H1 2026 is 10.15%. It is calculated by adding 8 percentage points to the ECB reference rate in force on the last working day of the previous semester (2.15% in December 2025). Source: BOE-A-2025-27201.

What is the €40 fixed compensation for collection costs?

Art. 8 of Law 3/2004 establishes that, upon late payment, the creditor is automatically entitled to a flat €40 for debt recovery costs. No expenses need to be justified. If documented recovery costs exceed that amount, the excess can also be claimed.

How is late payment interest calculated exactly?

The formula is: Interest = Principal × Annual rate × Days overdue / 365. For example, €1,000 × 10.15% × 30 days / 365 = €8.34. The fixed €40 compensation is added on top.

Can I claim interest even if the client has already paid?

Yes. If the client paid late, you are entitled to claim the interest accrued during the days of delay and the €40 compensation, even if the principal has been collected. The right does not expire upon late payment.

Does Law 3/2004 apply to all commercial transactions?

It applies to transactions between businesses or between businesses and public authorities involving the delivery of goods or provision of services in exchange for payment. It does not apply to consumers (B2C). For self-employed professionals invoicing companies, it does apply.

Can I claim late-payment interest from a Public Administration?

Yes. Ley 3/2004 also applies to commercial operations with Spanish Public Administrations. The legal payment term for AAPP is 30 days, but the clock starts from invoice approval (Art. 198 LCSP), not the invoice date. The AAPP may have up to 30 prior days to verify and approve the work. Once 30 days have passed since approval, the same commercial late-payment interest and €40 recovery cost apply.

What is the statute of limitations on late-payment interest?

Commercial late-payment interest is subject to a 5-year limitation period (Art. 1964 Civil Code after the 2015 reform). The clock starts on the day the debt became enforceable. Claiming early in writing (e.g. burofax) interrupts the limitation and strengthens evidence if you go to court.

Late payment interest on unpaid invoices

Calculate how much you can claim for an invoice not paid on time. Legal rate H1 2026: 10.15%. Fixed €40 compensation included.

Invoice amount

€

Total invoice amount (ex-VAT), or the outstanding balance

Invoice date

Date you issued or delivered the invoice

Agreed payment deadline(optional)

Maximum 60 calendar days for B2B transactions (Art. 4.3 Law 3/2004)

Actual payment date(optional)

Leave blank if the invoice is still unpaid (we will use today)

Enter the amount and dates to calculate

Indicative calculation based on Law 3/2004 on combating late payment. The H1 2026 rate (10.15%) is verified in BOE-A-2025-27201. For real claims, consult your accountant or lawyer.

How to use the calculator

Follow these steps to calculate the late payment interest and compensation you can claim on an unpaid invoice.

Enter the amount

Type the unpaid invoice amount in euros. This can be the total or just the outstanding balance.

Enter the dates

Enter the invoice date and the agreed payment deadline. If no deadline was agreed, the law applies 30 calendar days.

Get the result

The calculator applies the current legal rate (10.15% H1 2026) and adds the fixed €40 debt-recovery compensation.

Use the data to claim

With the breakdown in hand, you can include the interest and compensation in your formal claim or client communication.

Why use this calculator

Knowing your rights as a creditor helps you collect what you are owed without needing intermediaries.

Up-to-date legal rate

The H1 2026 rate (10.15%) is verified in the Official State Gazette. It is updated every semester based on the ECB reference rate.

Compensation included

Art. 8 of Law 3/2004 entitles you to a fixed €40 per unpaid invoice for debt recovery costs, with no need to justify expenses.

No registration needed

No account creation, no data stored. Enter the figures and get the result instantly.

Frequently asked questions about late payment interest

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