Send the first letter the day after the due date, then move to firmer ones as the days pass. If the customer is a UK business, you can add statutory interest and a fixed sum (GOV.UK). Keep each letter to facts: invoice, amount, due date and what happens next. This is a template, not legal advice.
| Days overdue | Letter and tone |
|---|---|
| 1 to 14 | Friendly reminder. Assume it slipped. |
| 14 to 30 | Overdue notice, with the interest wording. Clear and calm. |
| 30 or more | Final demand with a date. Firm, and no threat you will not carry out. |
12 letters you can copy
Twelve letters for a business customer who has not paid, grouped by how late the invoice is. The letters are for business to business debts only. Replace every [BRACKET] with a real fact.
Jump to: The plain noticeTwo to four weeks late: overdue noticeA month or more late, and afterwards
- One day to two weeks late: the plain noticeSubject: Invoice [NUMBER]: payment due [DATE][YOUR NAME] [YOUR ADDRESS] [DATE] [CUSTOMER NAME] [CUSTOMER ADDRESS] Dear [NAME], Invoice [NUMBER] for [AMOUNT] was due on [DUE DATE]. I cannot see a payment. A copy is enclosed. Please pay by [DATE] using [PAYMENT DETAILS]. If you have already paid, please tell me the date and I will check my account. Yours sincerely, [YOUR NAME]
- Two weeks late: sent to the wrong person firstSubject: Invoice [NUMBER] sent to [NAME]Dear [NAME], On [DATE] I sent invoice [NUMBER] for [AMOUNT] to [FIRST PERSON]. I now think it may not have reached the person who pays invoices. I have enclosed it again. Could you tell me who deals with payments at [COMPANY] and when I can expect this to be paid? It was due on [DUE DATE]. [YOUR NAME]
- Two weeks late: bank details repeatedSubject: Payment details for invoice [NUMBER]Dear [NAME], Invoice [NUMBER] for [AMOUNT] is [NUMBER] days past its due date. To make paying easy, here are the details again: Account name: [NAME] Sort code: [CODE] Account number: [NUMBER] Reference: [REFERENCE] Please pay by [DATE]. [YOUR NAME]
More examples, by situation
Two to four weeks late: overdue notice
- Overdue notice, interest not yet addedSubject: Overdue: invoice [NUMBER]Dear [NAME], The payment for invoice [NUMBER], [AMOUNT], was due on [DUE DATE], [NUMBER] days ago. Please pay by [DATE]. [ADD IF TRUE: I may add interest and a fixed sum for late payment if it is not paid by then.] Details are on the enclosed copy. Yours sincerely, [YOUR NAME]
- Overdue notice with interest and the fixed sum addedSubject: New invoice [NUMBER]: invoice [OLD NUMBER] plus interestDear [NAME], Invoice [OLD NUMBER] for [AMOUNT] was due on [DUE DATE]. It is [NUMBER] days overdue. I have added: Interest at [RATE]% a year (8% plus the Bank of England base rate) from [DUE DATE] to [DATE]: £[AMOUNT] Fixed sum for late payment: £[40, 70 OR 100] New total: £[TOTAL]. A new invoice, [NEW NUMBER], is enclosed. Please pay by [DATE]. [ADD IF TRUE: Our agreement does not set a different rate of interest.] [YOUR NAME]
- A customer who has said "it is on its way" twiceSubject: Invoice [NUMBER]: payment dateDear [NAME], On [DATE] and [DATE] you told me payment was on its way. I have not received it. Please send me the date the money left your account, or a transfer reference I can trace. If I do not hear by [DATE], I will write again with the interest due. [YOUR NAME]
- A customer who disputes one lineSubject: Invoice [NUMBER]: the undisputed amountDear [NAME], I have noted your query about [LINE]. I will look at it and reply by [DATE]. The rest of the invoice, £[AMOUNT], is not in question. Please pay that part by [DATE]. We can settle the disputed line separately. [YOUR NAME]
A month or more late, and afterwards
- Final demand, with a dateSubject: Final demand: invoice [NUMBER]Dear [NAME], Invoice [NUMBER] for £[AMOUNT] was due on [DUE DATE]. With interest to [DATE] of £[AMOUNT] and the fixed sum of £[AMOUNT], you owe £[TOTAL]. This must reach my account by [DATE]. [PICK ONE: If it does not, I will [THE REAL NEXT STEP]. / I will then decide what to do next.] [YOUR NAME]
- Final demand when part has been paidSubject: Final demand: balance of invoice [NUMBER]Dear [NAME], Thank you for the payment of £[AMOUNT] on [DATE]. The balance of £[AMOUNT] on invoice [NUMBER] is still unpaid, and was due on [DUE DATE]. Please pay it by [DATE]. Interest is calculated on the balance only, and is £[AMOUNT] to [DATE]. [YOUR NAME]
- Confirming a payment plan they asked forSubject: Payment plan for invoice [NUMBER]Dear [NAME], Following your request, I agree to take £[AMOUNT] on [DATE], £[AMOUNT] on [DATE] and the last £[AMOUNT] on [DATE]. [ADD IF TRUE: I will not add further interest while each payment arrives on time.] If a payment is missed, the full balance falls due. Please reply "agreed" to confirm. [YOUR NAME]
- Thank you, when they paySubject: Payment received: invoice [NUMBER]Dear [NAME], Thank you. I received £[AMOUNT] on [DATE]. [PICK ONE: I have waived the interest. / The interest of £[AMOUNT] is still due and is on the enclosed invoice.] I look forward to working with you again. [YOUR NAME]
- A note for your own fileInvoice [NUMBER]. Amount: £[AMOUNT]. Due: [DATE]. Letters sent: [DATE, HOW SENT] / [DATE, HOW SENT]. Interest rate used: [RATE]%, source and date: [WHERE YOU READ IT]. Daily interest: £[AMOUNT]. Fixed sum added: £[AMOUNT]. Keep this with the letters.
Download these examples
The same text as this page, in one file, with the gaps ready to fill in.
What to avoid
- Threatening court action you do not mean to take, or naming any legal step beyond what GOV.UK says.
- Adding interest for a private customer. The rule is for business customers.
- Charging the fixed sum more than once for the same payment. GOV.UK says once for each payment.
- Quoting the base rate from memory. Use the date and the source on this page.
- Writing about credit files or debt collectors.
Official pages. Rules differ by country. Not legal advice: check the rules that apply to you.
- GOV.UK: Late commercial payments: when a payment becomes late. It says: "If you do not agree a payment date, the law says the payment is late 30 days after either: the customer gets the invoice; you deliver the goods or provide the service (if this is later)." Read 5 October 2026.
- GOV.UK: Interest on late commercial payments. It says: "The interest you can charge if another business is late paying for goods or a service is 'statutory interest' - this is 8% plus the Bank of England base rate for business to business transactions. You cannot claim statutory interest if there's a different rate of interest in a contract." Read 5 October 2026.
- GOV.UK: Claim debt recovery costs on late payments. The fixed sum is £40 up to £999.99, £70 from £1,000 to £9,999.99 and £100 for £10,000 or more. It says: "You can only charge the business once for each payment." Read 5 October 2026.
- GOV.UK: Make a court claim for money. It says: "You can apply to a county court to claim money you're owed by a person or business" and "A mediation service could be quicker and cheaper than going to court." Read 5 October 2026.
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Let the tool do the sums
It is free. It works out the interest and the fixed sum from your invoice.
Late Payment Chaser (UK)
What you give it: The unpaid amount, the invoice date, and the due date if you agreed one.
What you get: What you can claim under UK late-payment law, worked out with a script and shown with official sources, and three reminder emails to send. UK business-to-business debts only. Not legal advice.
Free. It also works as a paste-in text in a chatbot; there the assistant does the arithmetic, so check its working.
What is the difference between a reminder and a final demand?
A reminder assumes the invoice slipped. A final demand gives a date and says what you will do next, if you really mean to do it.
Can I charge a fixed sum on a late invoice?
For a business customer, GOV.UK lists £40, £70 or £100 by size of debt, charged once for each payment.
How long before an invoice counts as late?
If no date was agreed, GOV.UK says 30 days after the customer gets the invoice or after you deliver, if that is later.
Do I need to send a new invoice if I add interest?
GOV.UK says to send a new invoice if you decide to add interest to the money you are owed.
Questions people ask
What do I do with the [BRACKETS]?
Replace each one with a real fact. If you cannot, delete the line. Never leave a bracket in what you send.
How do I write a late payment letter?
Facts first: the invoice number, the amount, the due date, how many days late it is, how to pay, and what you ask for by when. Then, if you have decided to add interest, say so and send a new invoice.
What is a final demand letter?
It is the last letter before you take another step. Name that step only if you really mean to take it. GOV.UK says a county court claim exists, and that mediation may be quicker and cheaper.
Can I add interest to a late payment letter?
For a business customer, yes. GOV.UK says the rate is 8% plus the Bank of England base rate. The base rate was 3.75% from 18 December 2025 (read 5 October 2026). The calculator page shows which base rate applies to your due date. GOV.UK also lists a fixed sum of £40, £70 or £100 by size of debt, charged once for each payment. You cannot claim statutory interest if a contract sets a different rate. Not legal advice.
When is a payment late?
If you did not agree a date, GOV.UK says the payment is late 30 days after the customer gets the invoice, or after you deliver the goods or provide the service if that is later.
Should I send a letter or an email?
The words can be the same. A posted letter helps if you may claim later, because you keep a copy and the date you sent it. That is practical advice, not a legal rule.
More
Sources
- Late commercial payments: when a payment becomes late, read 5 October 2026
- Interest on late commercial payments, read 5 October 2026
- Claim debt recovery costs on late payments, read 5 October 2026
- Make a court claim for money, read 5 October 2026