How to remind a customer about an overdue invoice

Send a short, polite email that names the invoice, the amount and the original due date, attaches a copy of the invoice, and tells the customer exactly how to pay. Send it from your own email address, follow it with a firmer reminder if nothing changes, and stop as soon as the customer replies that they have paid or have a query. If a customer owes on several invoices, put them all in one email rather than sending one email per invoice.

When should I send a payment reminder?

A simple schedule works for most businesses. Adjust the days to fit your payment terms and your relationship with the customer.

• Before the due date (about 3 to 5 days before): a courtesy note that the invoice is coming due.
• On the due date: a brief note that payment is due today, with the payment details.
• 7 days overdue: the first overdue reminder. Friendly, factual, and it asks the customer to confirm a payment date.
• 14 to 21 days overdue: the second reminder. Firmer, and it asks for a reply.
• Final reminder: a clear statement of what happens next if payment is not received by a specific date, for example that further supply will be put on hold or that the matter will be passed on in line with your terms.

Before each send, check that the invoice is still unpaid.

What should a payment reminder include?

• The invoice number, invoice date, amount and original due date.
• The total currently overdue, if there is more than one invoice.
• A copy of each invoice attached as a PDF, so the customer does not need to ask for it.
• How to pay: bank details, a payment link, or both.
• A clear request: pay by a date, or reply with a payment date.
• A named person to reply to, and a reply address that reaches them.

Keep the subject line specific and calm. A subject that names the invoice and the amount gets opened; one that shouts gets ignored or filtered.

• Good: "Invoice 1234 overdue: EUR 2,500.00 due 1 October"
• Good: "Overdue balance: EUR 7,500.00 across 3 invoices"
• Avoid: "URGENT!!! Payment required immediately"
• Avoid: "Following up"

What wording should I use for each reminder?

First reminder (about 7 days overdue)

Subject: Invoice [number] is now overdue

Dear [Customer name],

I hope you are well. Our records show that invoice [number] for [amount], due on [due date], has not yet been paid. A copy is attached for reference.

If payment is already on its way, thank you, and please disregard this message. Otherwise, could you let me know when we can expect it?

Kind regards, [Your name]

Second reminder (14 to 21 days overdue)

Subject: Second reminder: invoice [number], [amount] overdue

Dear [Customer name],

I am following up on invoice [number] for [amount], which was due on [due date] and is now [number of days] days overdue. We have not yet received payment or a reply to our earlier reminder.

Please arrange payment by [date], or reply to this email with a payment date or any question about the invoice. A copy is attached.

Kind regards, [Your name]

Final reminder

Subject: Final reminder: invoice [number] overdue since [due date]

Dear [Customer name],

Invoice [number] for [amount] remains unpaid, despite our reminders of [date] and [date]. Please arrange payment by [date].

If we do not receive payment or hear from you by then, we will [put further orders on hold / take the next step set out in our terms]. If there is a problem with the invoice, please reply today so we can resolve it.

Kind regards, [Your name]

Only state a consequence you are prepared to carry out, and make sure it matches your agreed terms.

One reminder for several invoices

Subject: Overdue balance: [total] across [number] invoices

Dear [Customer name],

The following invoices are open on your account. Copies are attached.

Invoice	Amount	Due date	Status
1234	EUR 2,500.00	1 Sep	14 days overdue
1235	EUR 3,000.00	8 Sep	7 days overdue
1236	EUR 2,000.00	15 Sep	Due in 2 days

Total open: EUR 7,500.00, of which EUR 5,500.00 is overdue.

Please arrange payment of the overdue amount by [date], or reply with a payment date or any question about these invoices.

Kind regards, [Your name]

What tone should a payment reminder take?

Polite, factual and specific. Assume the delay is an oversight until you have reason to think otherwise. Avoid sarcasm, capital letters, and phrases that suggest blame. Each reminder can be firmer than the last, but the firmness should come from clearer dates and next steps, not from harsher language.

Should I send one email per invoice or one per customer?

One per customer. If a customer owes on four invoices, four separate reminders arriving in the same morning look automated and are easy to overlook. One email that lists every overdue invoice, shows the total, and attaches each PDF gives the customer's accounts team everything they need in one place.

What should I do when the customer replies?

"We have already paid." Stop reminders for that customer straight away. Thank them, ask for the payment date and reference, and check your bank records. If the payment has arrived, record it. If it has not, reply with the details you hold and ask them to check with their bank.

They dispute the invoice. Stop reminders on the disputed invoice while you look into it. Acknowledge the query, say when you will come back to them, and resolve it before you send another reminder about that invoice. Continue to remind about any other invoices that are not in dispute.

They promise to pay on a date. Note the date and do not send another reminder before it. If the date passes without payment, refer to their promise in your next reminder.

No reply at all. Move to the next reminder in your schedule.

How does Reminder help with this?

Reminder reads your open invoices from QuickBooks, Xero or Zoho Books (or from uploaded PDFs) and drafts one reminder email per customer covering all their overdue invoices, with the invoice PDFs attached. You check each draft and press send; it goes from your own email domain. It tracks disputes and promises to pay, so the next reminder takes them into account.

FAQ

How many reminders should I send before a final notice? Usually two or three: one around the due date, one about a week after, and one firmer reminder two to three weeks after. Then a final reminder with a clear date.

Should I attach the invoice to the reminder? Yes. Attaching the PDF removes the most common reason for further delay, which is a request for a copy.

Can I send reminders automatically? You can, but check each reminder against current payments before it goes. A short review step avoids reminding a customer who has just paid.

What if the customer pays part of the amount? Thank them, record the part payment, and send a reminder for the remaining balance that shows the amount received and the amount still due.