Overdue Invoice Email Template: 6 Emails From Day 1 to Day 45

An overdue invoice needs a sequence, not a single email. The first message should assume an honest mistake. The last should make the next step unmistakable. Everything in between should get a little more specific without getting rude.

Below are six templates for the six moments that matter, from the day after the due date to the final notice. Each has a subject line, the email, and a note on when to change it.

Before you send anything

Check three things, because nothing undermines a reminder faster than an error in it:

1. The invoice actually went out, to the right person and address.
2. The amount and due date match what the client agreed.
3. A payment hasn't just arrived. Check your bank and payment provider first.

Then keep every email to a few lines, with the invoice number, amount, due date and a way to pay. If you'd like a version tailored to your details, the payment reminder generator will fill these in.

1. Day 1 overdue: the friendly check

Subject: Invoice INV-1042 was due yesterday

Hi Sam,

A quick note that invoice INV-1042 for €2,400 was due yesterday, 2 April. It may already be on its way. If not, here's the payment link: [link]. Bank details are on the invoice.

Thanks, [Your name]

When to change it: if you sent a pre-due reminder, mention it: "Following on from my note last week…"

2. Day 7: the polite follow-up

Subject: Following up: invoice INV-1042 (€2,400)

Hi Sam,

I'm following up on invoice INV-1042 for €2,400, which was due on 2 April. Could you let me know when it's scheduled for payment? I've attached it again in case it got lost.

Payment link: [link]

Thanks, [Your name]

Why it works: "When is it scheduled?" is a question with a concrete answer. It's harder to ignore than "just checking in".

3. Day 14: the specific ask

Subject: INV-1042: 14 days overdue

Hi Sam,

Invoice INV-1042 for €2,400 is now two weeks overdue. Is there anything holding it up on your side, such as a missing PO number or a question about the work? If so, tell me and I'll sort it today.

Otherwise, could you arrange payment by Friday 18 April? Here's the link: [link].

Thanks, [Your name]

When to change it: if the client has a finance team, copy them in or ask Sam who to contact. Many invoices stall because the right person never saw them. See what to do when a client says accounting is processing your invoice.

4. Day 21: the phone call or a different channel

Not every step should be an email. If three emails have gone unanswered, call, or send a short message on the channel you normally use with the client.

Hi Sam, [Your name] here. I've emailed a couple of times about invoice INV-1042 for €2,400, due 2 April. Is everything OK? Could you check where it is?

Silence after three emails often means the emails aren't being seen. Our guide on why clients ignore invoice emails covers the common reasons.

5. Day 30: the firm reminder

Subject: INV-1042: 30 days overdue, please confirm a payment date

Hi Sam,

Invoice INV-1042 for €2,400 is now 30 days overdue. I haven't heard back on my last messages, so I want to make sure this is resolved.

Please confirm a payment date by Wednesday 7 May. Under our terms, late payments incur statutory interest and €40 compensation. I'd rather not apply them, and won't if it's paid by then.

Payment link: [link]

Thanks, [Your name]

When to change it: use the right legal reference for your region, or remove that paragraph if you prefer to keep it in reserve. See late fee wording on an invoice.

6. Day 45: the final notice

Subject: Final notice: invoice INV-1042

Hi Sam,

This is a final notice for invoice INV-1042 for €2,400, due on 2 April and now 45 days overdue.

If payment isn't received by Friday 23 May, I'll [pause further work / add statutory interest and compensation / start a formal recovery process]. I'd much prefer to resolve this directly, so if there's a problem, please reply today.

Payment link: [link]

[Your name]

The rule for final notices: only state a consequence you'll actually carry out. More on this in final notice letter for an unpaid invoice.

Subject lines that get opened

• Include the invoice number. It's what the client's finance team searches for.
• Put the amount in the first or second email. It helps people prioritise.
• Keep it factual: "Invoice INV-1042 was due on 2 April" works better than "Friendly reminder!!".
• Avoid words that look like spam or phishing: "URGENT", "ACTION REQUIRED", lots of capitals.

Tone, stage by stage

• Day 1–7: assume it was missed. No mention of fees.
• Day 14: ask what's blocking it. Offer to help.
• Day 21: change channel.
• Day 30: set a date. Mention terms if you want to.
• Day 45: final notice with one clear consequence.

For a softer approach with long-term clients, see polite escalation scripts. For pre-due reminders, see payment reminder before the due date.

FAQ

How do you write an email for an overdue invoice?

Keep it short. Include the invoice number, amount, original due date and a payment link, and ask a specific question, such as when it's scheduled for payment.

How soon should I send an overdue invoice reminder?

The first working day after the due date. Waiting a week signals the deadline didn't matter.

How many reminders should I send?

Typically four to six over 30 to 45 days, ending with a final notice. Change channel if emails go unanswered.

Should I attach the invoice again?

Yes, from the second reminder on. It removes the "I can't find it" delay.

Send the sequence without writing it every time

DueChat sends polite reminders like these in your name at 7, 14 and 30 days overdue, with your pay link, and stops automatically when the client pays. €19/month or €190/year after a 30-day trial. See how reminders work.