AnswersWhen a client won't pay
What should a payment reminder email say at each stage?
The short answer
Five emails. One a week before the due date, one on it, then on days 7, 14 and 30, each one firmer. The first asks if the invoice arrived: with no date agreed, the 30 days start no earlier than the day they get it1. The fourth states 8% interest above the base rate2 and the fixed £40, £70 or £1003 to the penny; the fifth is the letter before action.
England and Wales only. WolfX is software, not a law firm.
What you can add
A £3,600 invoice, 30 days late
Say you invoiced another business £3,600 on 31 August 2026, due on 30 September. The five emails go on 23 September, 30 September, 7 October, 14 October and 30 October. The law sets none of these reminder days. It does set when interest starts7: 1 October, the day after the due date. The rate is set by the Bank Rate on 30 June4, which was 3.75%5, so 8% over it is 11.75% a year.
From there interest adds £1.16 a day, and the £70.00 stays put. At 60 days late the interest would be £69.53 and the total £3,739.53. The day-14 email works the same sum to 14 days: interest of £16.22 and a total of £3,686.22. The letter before action on day 30 states the sum above.
The road ahead
Five emails, on five set days. One stamp.
Step 1: A week before it's due: check it arrived
Ask one thing: did the invoice arrive, and is it with the person who pays? Subject: Invoice 1187 (£3,600.00) due 30 September: received? Attach the invoice again.
If no date was agreed, an invoice that did not arrive may not have started the clock. If they name someone else, send every later email to that person; if nobody answers, phone.
Step 2: On the due date: send one line
Subject: Invoice 1187 (£3,600.00) is due today. Body: the number, the amount, the bank details, the invoice attached. No question and no apology, because a due date is a fact.
If they answered the first email with a payment date, skip this one and put that date in your diary.
Step 3: 7 days late: first reminder, ask for a date
Subject: Invoice 1187 (£3,600.00): when will it be paid? Body: it was due on 30 September and is unpaid. Could you confirm the date payment will be made? Attach the invoice again.
Expect back, usually, a date, the name of someone else to send it to, or a reason. Any of the three is progress.
Step 4: 14 days late: firm reminder, with the sum worked out
Send the email below as a reply on the same thread. It repeats the amount and the due date, sets a pay-by date 14 days ahead and works out the sum: interest has been running7 since 1 October at 11.75% a year5, £16.22 so far, plus the £70.00 fixed sum.
Attach a new invoice2 for the two and leave the original as it was. Some call this email a final demand, which is not a legal term. If it is not paid by the pay-by date, the next letter is the letter before action.
Step 5: 30 days late: send the letter before action
Send the letter before action by email and post. The line that matters: "Interest of £34.77 and the fixed sum of £70.00 are due under the Late Payment of Commercial Debts (Interest) Act 1998, so the total today is £3,704.77, and interest adds £1.16 a day. Please pay in full by 13 November 2026. If it is not paid by then, I will start a court claim."
Send a second interest invoice for the extra £18.55, so the three invoices add up to £3,704.77. A company usually gets 14 days8; a sole trader gets 309, so move the date. If the date passes, the next step is the claim.
A letter you can copy
Day-14 reminder: firm, with the sum worked out
Send it 14 days after the due date, as a reply to your day-7 email, when no payment or date has come back.
Tap a highlighted gap to see what goes in it.
Reply on the thread of your day-7 email, so the whole run sits in one place with dates on it. Send it to whoever approves payments and copy in whoever ordered the work. Keep the invoice number and amount the same as in every earlier email. If they gave a date and missed it, change the sentence about your day-7 email to say so. Keep the sentence about the letter before action only if you will send it on day 30. A date you do not keep makes the next one worth less.
When not to bother
When it isn't worth it
- They have disputed the invoice. Reminders will not settle it. Ask in writing which item they dispute and what sum it covers, then ask for the rest by a date: the disputed part waits, the rest is usually still due.
- The customer is a public body with its own invoice portal. Look at the invoice's status there before you write. Their payment date must usually be within 30 days1, so the clock runs shorter.
- The customer is a consumer. The interest and the fixed sum only cover sales between businesses6. Consumer debts follow other rules, and this page does not cover them.
- They have given you a payment date in writing and it has not passed. Wait for it, and put the day after it in your diary.
- You are in Scotland or Northern Ireland. The letter before action and the court claim here are for England and Wales; the other two nations have their own court process10.
The Wolf's note
Put all five dates in your diary the day the invoice goes out, and each email becomes a task with a day on it. The fourth names the sum; the fifth is the letter before action. After it, the next move is a formal one.
Mr. Wolf · the AI inside WolfX
What comes next
Your next move
How do I chase an overdue invoice politely?
Two short emails: on day 7, ask for a payment date; on day 14, name one, with the interest and fixed sum worked out.
5 min read · Letter included
My client hasn't paid my invoice. What do I do first?
Check the invoice, then ask once, in writing, for a date.
6 min read · Letter included
What you can add
Can I charge interest on a late invoice?
Yes, if you sold to another business.
3 min read · Letter included
Don't want to do this yourself?
The Wolf does every step for you. He works out the sums, writes the letters and keeps track of every date. Nothing goes without your yes.