Write a reminder for an overdue invoice

Short answer

This invoice payment reminder generator writes an English reminder draft from your invoice number, amount, due date and days overdue, in one of three tones: friendly, firm or final. For business customers in the EU it can add statutory late-payment interest (reference rate plus 8 percentage points) and the €40 fixed compensation. You copy the draft; nothing is sent.

How to use the invoice payment reminder generator

1. Enter the invoice details: invoice number, the outstanding amount including VAT, and the due date. The tool counts the days overdue from the due date to today; you can overwrite the number.
2. Choose the stage. Stage 1 is a friendly reminder, stage 2 a firm second reminder, stage 3 a final reminder.
3. Add optional details: the customer's name, your name and company, and payment details such as your IBAN.
4. Decide on statutory claims. If the customer is a business or a public authority, you can tick the option to add statutory interest and the €40 compensation. Enter the reference rate yourself (see below); leave it blank and the draft mentions interest without an amount.
5. Copy the draft, read it, adjust it to your relationship with the customer, and send it from your own email or letter template.

The generator is deliberately a draft tool. It does not send email, does not store your invoices and does not track whether the customer paid. All calculation happens in your browser.

What should an overdue invoice reminder include?

A reminder that gets paid is short, specific and easy to act on. Each draft contains:

Asking the customer to quote the invoice number as the payment reference is not just politeness. When a payment arrives without the reference, someone has to work out which invoice it belongs to. If you want to test how a reference survives a bank transfer, use the SEPA transfer reference checker.

Three reminder stages: friendly, firm and final

The final reminder does not threaten specific legal action. What happens next (a collection agency, a court order procedure, stopping supplies) depends on your country and your contract, and it is better to decide that deliberately than to promise it in a template.

You do not need to send any reminder before statutory interest starts. Under the Late Payment Directive, interest is due without a reminder once the payment date has passed. Reminders are about getting paid, not about creating the right to interest.

How is statutory late-payment interest calculated in the EU?

Directive 2011/7/EU on combating late payment in commercial transactions applies to payments between businesses and between businesses and public authorities. Its main rules, as written in the directive:

• Rate: statutory interest is simple interest at the reference rate plus at least eight percentage points (Article 2(6)).
• Reference rate: in euro-area countries, the European Central Bank's rate on its most recent main refinancing operations. The rate in force on 1 January applies to the first half of the year, and the rate on 1 July to the second half (Articles 2(7), 3(2) and 4(2)).
• Start: interest runs from the day after the agreed payment date or the end of the payment period (Article 3(3)(a)). Without an agreed date, it starts 30 days after the customer received the invoice.
• Amount: the sum due includes the VAT and other taxes shown on the invoice (Article 2(8)).
• No reminder needed: interest is due "without the necessity of a reminder" if you met your own obligations (Article 3(1)).

The generator uses this formula:

Interest = outstanding amount × (reference rate + 8) % × days overdue ÷ 365, rounded to the nearest cent.

The directive does not say whether to count a year as 365 days, nor how to split a period that crosses 1 January or 1 July. We use 365 days and one rate for the whole period, which matches the worked example published by the Irish government. For a long overdue period that crosses a half-year boundary, calculate each part separately with its own rate.

Which reference rate do you enter?

The generator does not fill in the rate for you, because the right number depends on the country and the date, and a stale default would be worse than none.

• On the ECB's key interest rates page, the main refinancing operations rate was 2.40% from 17 June 2026 and 2.65% from 16 September 2026. For the second half of 2026, the rate in force on 1 July (2.40%) is the reference, giving a statutory rate of at least 10.40% in countries that apply the ECB rate plus 8 points.
• Some countries apply a different base or a higher margin. Germany, for example, uses the Bundesbank base rate plus 9 points for business transactions (1.52% + 9 = 10.52% from 1 July 2026). Enter 1.52 + 1 = 2.52 to make the generator produce 10.52%, or calculate separately.
• Non-euro EU countries use their national central bank's rate.

The European Commission's Your Europe portal publishes a table of national late-payment rates. Use it as a starting point, but check the national source, because we found entries there that did not match the current ECB rate.

Worked example

Invoice INV-2026-0042 for €4,800.00 (including VAT) to a business customer was due on 15 September 2026. On 5 November 2026 it is 51 days overdue. The reference rate for the second half of 2026 is 2.40%.

1. Statutory rate: 2.40 + 8 = 10.40% a year.
2. Interest: €4,800.00 × 10.40% × 51 ÷ 365 = €69.75 (69.75123 rounded).
3. Fixed compensation: €40.00.
4. Total claimed: €4,800.00 + €69.75 + €40.00 = €4,909.75.

The simpler cross-check from the Irish government's example: €1,000 overdue for 25 days at 10.40% gives €1,000 × 0.104 × 25 ÷ 365 = €7.12. The generator's tests use exactly this case.

The calculation uses whole cents and whole hundredths of a percent, with integer arithmetic, so there is no floating-point rounding drift.

The €40 fixed compensation: when it applies

Article 6 of the directive gives a creditor who is entitled to late-payment interest a fixed sum of at least €40 as compensation for recovery costs, without a reminder. You may also claim reasonable recovery costs above €40, such as the cost of a lawyer or collection agency (Article 6(3)). A contract term excluding the compensation is presumed grossly unfair (Article 7(3)).

The generator adds €40 once per reminder draft, for the one invoice you entered. It does not add costs beyond that, because they need evidence.

When statutory interest does not apply

• Consumers. The directive covers commercial transactions only. You cannot use it to claim interest or €40 from private individuals. If you untick "business or public authority", the generator leaves these claims out even if you tick the interest option.
• Your contract says otherwise. Contracts can set a different interest rate or payment term within limits; a term that excludes interest altogether is grossly unfair under Article 7(2).
• Disputed invoices. If the customer is not responsible for the delay, interest is not due.

Payment terms in business transactions may not exceed 60 calendar days unless expressly agreed and not grossly unfair to the creditor; public authorities normally have 30 days. A proposed Late Payment Regulation (COM(2023) 533) would replace the directive with stricter limits, but on 5 November 2026 the European Parliament's legislative observatory still listed it as awaiting the Council's first-reading position. The directive, as transposed in each country, remains the law.

What this generator does not do

• It does not send, schedule or track reminders. Automated reminders are part of our planned collections product, which is not available yet.
• It is English only.
• It does not know your national law in detail and is not legal advice. The author is not a lawyer.
• It does not check whether the invoice is already paid. Matching incoming payments to invoices is what the reconciliation product is for; you can try the logic in the reconciliation demo with sample files.

Frequently asked questions

When should I send the first payment reminder?

There is no legal rule. Many businesses send a friendly reminder a few days after the due date, a firmer one a week or two later, and a final reminder after that. Choose a rhythm you will actually keep.

Can I charge late-payment interest to a consumer?

Not under the Late Payment Directive, which covers transactions between businesses and with public authorities. National consumer rules may allow default interest in some cases; check them before claiming anything.

Do I need to send a reminder before interest starts?

No. Under the directive, statutory interest is due from the day after the payment date without a reminder, provided you met your own obligations.

How is late-payment interest calculated?

Multiply the outstanding amount by the statutory rate (reference rate plus at least 8 points) and by the days overdue, then divide by 365. The worked example above shows each step.

Is the €40 compensation per invoice?

The directive grants the fixed sum when interest becomes payable on a late commercial payment; the generator applies it to the single invoice in the draft. Check national guidance if you chase several invoices from the same customer.

Is anything I type stored or sent?

No. The draft is created in your browser and only leaves it when you copy and send it yourself.

Sources

• Directive 2011/7/EU on combating late payment in commercial transactions (text as adopted) (accessed 5 November 2026)
• European Central Bank — key ECB interest rates (accessed 5 November 2026)
• Your Europe — late payment (accessed 5 November 2026)
• Department of Enterprise, Tourism and Employment (Ireland) — late payment interest rate and worked example (accessed 5 November 2026)
• German Civil Code §288 — default interest and Deutsche Bundesbank — base rate (accessed 5 November 2026)
• European Parliament Legislative Observatory — procedure 2023/0323(COD) (accessed 5 November 2026)