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Demand letterfor an unpaid invoice.
Fill in the details and choose the tone: friendly reminder, formal demand or final demand before legal action. The letter writes itself as you type, in English or Spanish, with the late-payment interest and the €40 under Spain’s Late Payment Act (Law 3/2004) calculated as of today if you want to claim them.
- Nothing is sent or saved
- Three templates based on the law
- Copy, download or save as PDF
Step 1 · The details
Who is claiming what, from whom
Nothing is sent or saved: the letter is written in your browser.
As of today, 28 October 2026, at the statutory BOE rate for each half-year, as in the late-payment interest calculator. Only between businesses and self-employed professionals; no VAT. If unticked, the letter mentions that right without figures.
Step 2 · Your letter
Formal demand
Recommended delivery: by email or registered post.
6 gaps in square brackets still to fill in: complete them above, or later in your copy.
Enter the outstanding amount and the due date to calculate the interest and the €40 as of today.
- Templates for guidance only; they don’t replace a lawyer’s advice. Review the letter before sending it and attach a copy of the invoice.
- Between businesses and self-employed professionals. Law 3/2004 doesn’t apply to consumers: with a private individual, don’t add the interest or the €40.
- Nothing leaves your browser. It’s neither sent nor saved: if you close the page, the letter is lost.
Three templates
Which letter to send, and when
Chasing an unpaid invoice goes in steps: first a friendly reminder, then a formal demand and, if there’s still no reply, a final demand before a court payment order (monitorio). Raising the tone gradually helps you get paid without damaging the relationship, and leaves a written record that you tried.
- Template 1
Friendly reminder
For a good customer who’s running late. Polite, with all the details.
How to send it: by email.
- Template 2
Formal demand
If the first reminder got no reply. It mentions the interest and the €40 allowed by law.
How to send it: by email or registered post.
- Template 3
Final demand before legal action
The last notice before a court payment order (monitorio): it demands payment and invites the customer to negotiate, as required by the mandatory pre-litigation settlement step (MASC).
How to send it: by burofax with certified content and proof of delivery.
Debt demand letter template
What a demand letter should include
The letter has to make sense on its own, without looking anything up. The generator includes everything it shouldn’t be missing:
- Who is claiming from whom, with the company name and tax ID (NIF/CIF) of both businesses.
- The invoice claimed: number, issue date, due date and outstanding amount.
- The late-payment interest and the €40 for recovery costs, if you decide to claim them.
- A deadline to pay and how to do it, with your IBAN if you add it.
- What happens if they don’t pay: in the final demand, going to court, without exaggerating.
Attach a copy of the invoice and, if you have them, the purchase order or the signed delivery note: they’ll also help you in a monitorio. The templates are the same as in the guide debt demand letter (in Spanish), which explains how to send it so it counts and what to do depending on the customer’s reply.
Interest and €40
Demand for payment with late-payment interest
Between businesses and self-employed professionals, Spain’s Late Payment Act (Law 3/2004), on combating late payment in commercial transactions, puts the customer in default as soon as the payment term has passed, with no notice needed (Article 5). From the day after the due date, they owe interest at the agreed rate or, if there’s no agreement, at the statutory rate: the European Central Bank rate plus eight points, which the BOE, Spain’s Official State Gazette, publishes every half-year (Article 7). In H2 2026 it’s 10.40%. You can also claim €40 per invoice for recovery costs (Article 8). Neither the interest nor the €40 is subject to VAT.
If you tick the box, the letter includes the breakdown as of today, with the same calculation as the late-payment interest calculator, and states that interest keeps running until payment. Claiming it is a right, not an obligation: you can leave it out of the first reminder and ask for it in the final demand.
FAQ
Common questions about chasing an invoice
Do I have to send a demand letter before going to court?
No rule requires a “letter” as such, but since 3 April 2025 Organic Law 1/2025 requires an attempt at an appropriate dispute resolution method before filing a claim, the mandatory pre-litigation settlement step (MASC), including before a court payment order (monitorio). This tool’s final demand before legal action invites the customer to negotiate and identifies the invoice claimed, so it can help you meet that requirement if you send it by a method that proves receipt.
Do I need to send a demand to charge late-payment interest?
No. Between businesses and self-employed professionals, Article 5 of Spain’s Late Payment Act (Law 3/2004) puts the customer in default once the payment term has passed, with no notice or formal demand needed. The interest (Article 7) and the €40 for recovery costs (Article 8) are owed from the day after the due date, whether or not you claim them. The letter is how you ask for them and keep a record.
How should I send the letter so it counts as evidence?
The law doesn’t require a specific method, but you’ll need to prove what you sent, when, and that it arrived. Email works for the friendly reminder and the formal demand; for the final demand before legal action, use a burofax with certified content and proof of delivery, or a notarial demand.
How many days should I give the customer to pay?
The law doesn’t set a deadline for an out-of-court demand. The letters use ten days, which is the usual practice. The final demand before legal action, which invites the customer to negotiate, gives thirty calendar days: if the customer doesn’t reply within that period after receiving it, the negotiation is considered closed without agreement.
Does a demand letter interrupt the limitation period?
Yes. Article 1973 of the Spanish Civil Code includes the creditor’s out-of-court demand among the events that interrupt the limitation period, which then starts again from that point. For it to count, you must be able to prove that the demand arrived.
Can I use it if my customer is a private individual?
The letters, yes, but without ticking the interest and the €40: Law 3/2004 only applies to transactions between businesses and self-employed professionals, or with public authorities. With a consumer, the debtor is in default from when you demand payment (Article 1100 of the Spanish Civil Code), and what you agreed applies or, if there’s no agreement, the statutory interest rate (interés legal del dinero).
Is what I type into the generator saved?
No. The letter is written and calculated in your browser: no data is sent to any server and nothing is saved. If you close the page, it’s lost, so copy or download it first.
Keep reading
If the customer still doesn’t pay
- Debt demand letterWhat it should include, how to send it so it counts, and what to do depending on the customer’s reply.In Spanish
- Court payment order (monitorio) without a lawyerIf the demand doesn’t work: how to file a monitorio, step by step.In Spanish
- Acknowledgement of debtIf the customer admits the debt but can’t pay: template and effects.In Spanish
- Debt payment agreementIf they offer to pay in instalments: schedule, payment method and default.In Spanish
- Late-payment interest in 2026The commercial rate for each half-year, the tax rate and the statutory interest rate.In Spanish
- Late-payment interest calculatorInterest period by period plus the €40, to a payment date or to today.
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