How to follow up on an unpaid invoice, with email templates

The short answer

Follow up on the first working day after the due date, then about a week later, then at two weeks with a phone call, then with a final notice at around 30 days. Keep every message short, attach the invoice each time, and make paying the easiest thing to do. Escalate only after the final notice, and say in it what you will do next.

Why invoices go unpaid

Before writing anything, assume the boring explanation. In my experience, these cover nearly every late invoice:

• It went to the wrong person, or to a shared inbox nobody reads.
• It is waiting for someone to approve it, and that someone is on holiday.
• It is missing something the accounts team needs: a PO number, the right legal entity, a tax number.
• It missed the client's payment run and is waiting for the next one.
• The client has a cash problem and is paying the loudest suppliers first.

Only the last one is about money. The rest are fixed by a reminder that reaches the right person with everything they need. That is why the first reminders should be friendly and practical: anything else makes the four innocent cases awkward for no reason.

Before the due date

For larger invoices, a short note two or three days before the due date catches the lost-invoice problem while there is still time. It is not a reminder that they owe you; it is a check that the invoice arrived.

Subject: Invoice 2026-014 due on Monday

Hi Priya,

A quick check that invoice 2026-014 (GBP 4,356.00) reached the right
person. It is due on Monday, 19 October. I have attached it again
in case it is easier to forward.

Thanks,
Alex

Day 1 after the due date: the polite nudge

Send this on the first working day after the due date. Not a week later. The sooner you ask, the sooner it goes back into someone's queue.

Subject: Invoice 2026-014 is now due

Hi Priya,

Invoice 2026-014 for GBP 4,356.00 was due yesterday, 19 October.
I have attached it again. Could you let me know when it is scheduled
for payment?

If it is stuck on something from my side, such as a PO number or
an address, tell me and I will fix it today.

Thanks,
Alex

Two details make this work. You ask a question ("when is it scheduled?"), which gets a reply more often than a statement. And you offer to fix anything that might be blocking it, which flushes out the PO and approval problems.

Day 7: the firmer reminder

If there is no payment and no reply, send a second email to the same person and copy the project contact who hired you. The project contact is often the one who can walk over to accounts.

Subject: Overdue: invoice 2026-014, GBP 4,356.00

Hi Priya, hi Tom,

I have not yet received payment for invoice 2026-014 (GBP 4,356.00),
which was due on 19 October and is now a week overdue. The invoice
is attached.

Could you confirm the payment date, or tell me who I should contact
in accounts?

Thanks,
Alex

Notice that this is still polite. Firmer means more specific (the amount, the days overdue, a direct question), not ruder.

Day 14: call

By now email is not working. Phone the project contact or the accounts department. Calls get answers that emails do not, because it is harder to leave a person waiting on the line than an email in an inbox. Ask three things: has the invoice been received, has it been approved, and when is the payment date. Write down what they say, and send a short email afterwards confirming it:

Subject: Invoice 2026-014, as discussed

Hi Priya,

Thanks for the call just now. As discussed, invoice 2026-014
(GBP 4,356.00) has been approved and will be paid in the run
on 13 November.

I will look out for it.

Alex

That email turns a vague promise into a written date you can refer back to.

Day 21 to 30: the final notice

If the promised date passes, or there has still been no answer, send a final notice. This is the first message that mentions consequences. Be specific and calm, and only mention a step you are prepared to take.

Subject: Final notice: invoice 2026-014, 30 days overdue

Dear Priya,

Invoice 2026-014 for GBP 4,356.00 was due on 19 October and is now
30 days overdue. I sent reminders on 20 and 26 October, and when
we spoke on 2 November, payment was promised for 13 November.

Please arrange payment by 25 November. If I have not received it
by then, I will add statutory interest and compensation under the
Late Payment of Commercial Debts (Interest) Act 1998 and start
a claim to recover the debt.

Work on the remaining deliverables is paused until the account is
up to date.

The invoice and bank details are attached.

Regards,
Alex Marin

Adjust the legal reference to your country, or leave it out if there is none that applies. In the EU, the Late Payment Directive gives a similar right to interest and €40 compensation between businesses. In the US, use the late fee your contract set, if it set one.

Pausing work is often the most effective step, and you can take it without anyone's permission. It works best if your contract or quote said that work stops when invoices are overdue. Do not withhold files or delete work you have already been paid for, and check what your contract says about delivered work before you hold anything back.

When the reminders fail

If the final deadline passes, you have a few options, roughly in order of cost:

1. A formal letter before action, sent by post and email, giving a short final deadline (7 to 14 days is common) and saying you will start a claim. In England and Wales, the court's pre-action rules expect you to send one and give the debtor time to reply before you file. If the debtor is an individual or a sole trader, the Pre-Action Protocol for Debt Claims gives them 30 days.
2. A collection agency. They usually take a percentage of what they recover. Worth it for clients you will never work with again.
3. A small claims court. Most countries have a simple, low-cost procedure for small debts. In England and Wales you can file online through Money Claim Online. In the US, small claims limits are set by each state. Across EU borders, the European Small Claims Procedure covers claims up to €5,000.
4. A lawyer, for large amounts.

Before you file anything, work out whether it is worth your time. A claim for a few hundred against a client who has disappeared may cost more in hours than it recovers. A claim against an active company that simply ignored you often ends with payment as soon as the formal letter arrives.

Things that make the next invoice faster

Most of this is set up before the late invoice ever happens:

• Agree payment terms in writing before the work starts, including any late fee. See invoice payment terms.
• Ask who processes invoices and whether they need a PO number.
• Take a deposit on projects over a few days of work (how to invoice a deposit).
• Invoice the day the work is accepted, not at the end of the month.
• Put a due date on the invoice as a date, not only "Net 30".
• Keep a list of what is due and when, and check it on the same day every week. A reminder that goes out on day 1 gets paid sooner than one that goes out on day 20 because you forgot.

Tone

Keep every message about the invoice, not about the person. Do not apologise for asking; you did the work, and asking to be paid for it on the agreed date is normal business. Do not threaten anything you will not do. And never send a reminder when you are angry. Write it, leave it for an hour, and cut any sentence that does not move the payment forward.

If you want a starting draft for any stage, the payment reminder email generator writes one from the invoice details and how late it is, in a friendly, neutral or firm tone. And if the original invoice was missing something, the free invoice generator makes a clean one with the PO number, due date and payment details in place.

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