How to Follow Up on Unpaid Invoices: Email Templates That Work

How to Follow Up on Unpaid Invoices: Email Templates That Work

Following up on unpaid invoices feels uncomfortable, like you are begging for money you already earned. You are not, and how you ask makes all the difference. The right unpaid invoice follow-up email is professional, clear, and respectful. It reminds the client without shaming them, gets results without straining the relationship, and escalates in a measured way if the client goes quiet. Below are email templates for every stage of the process, with notes on when to reach for each one.

Before You Follow Up: Set Yourself Up for Success

Before you send any of these, make sure the invoice already does its job. It should carry a clear calendar due date (not just "Net 30" but the actual date), your contact information, every payment method and instruction, and an invoice number for easy reference. A complete, professional invoice makes the whole follow-up far simpler.

Template 1: Pre-Due-Date Reminder (3-5 Days Before)

Send this before the due date. It is a courtesy heads-up, not a chase.

Subject: Friendly reminder: Invoice #[NUMBER] due [DATE]

Hi [CLIENT NAME],

Just a quick heads-up that Invoice #[NUMBER] for [AMOUNT] is due on [DATE].

You can pay via [PAYMENT METHOD] at [LINK/DETAILS]. Let me know if you have any questions.

Thanks,
[YOUR NAME]

Template 2: Due Date Reminder (On the Due Date)

Send this on the due date itself if payment has not landed.

Subject: Invoice #[NUMBER] due today

Hi [CLIENT NAME],

Invoice #[NUMBER] for [AMOUNT] is due today, [DATE].

If you have already sent payment, please disregard this email. If not, you can pay via [PAYMENT METHOD] at [LINK/DETAILS].

Thanks for your prompt attention,
[YOUR NAME]

Template 3: First Follow-Up (5-7 Days Overdue)

Keep this casual and assume the invoice just got lost or forgotten. At this stage, most late payments are honest oversights.

Subject: Checking in on Invoice #[NUMBER]

Hi [CLIENT NAME],

I wanted to check in on Invoice #[NUMBER] for [AMOUNT], which was due on [DATE]. I have not seen payment come through yet, so I wanted to make sure it did not get lost in the shuffle.

You can pay via [PAYMENT METHOD] at [LINK/DETAILS]. Let me know if you need a copy of the invoice or have any questions.

Thanks,
[YOUR NAME]

Template 4: Second Follow-Up (14 Days Overdue)

The tone shifts a little here. Still professional and respectful, but more direct.

Subject: Invoice #[NUMBER], 14 days past due

Hi [CLIENT NAME],

Invoice #[NUMBER] for [AMOUNT] is now 14 days past its due date of [DATE]. I would appreciate payment as soon as possible.

If there is an issue with the invoice or a reason payment has been delayed, please let me know so we can work it out. Otherwise, payment can be made via [PAYMENT METHOD] at [LINK/DETAILS].

Thank you,
[YOUR NAME]

Template 5: Third Follow-Up (30 Days Overdue)

Now you are firmer. Consider whether late fees apply under your contract.

Subject: Final reminder: Invoice #[NUMBER], 30 days overdue

Hi [CLIENT NAME],

Invoice #[NUMBER] for [AMOUNT] is now 30 days past due. I have sent several reminders and have not received payment or a response explaining the delay.

[IF LATE FEES APPLY: Per our agreement, a late fee of [AMOUNT] has been added, bringing the total due to [NEW TOTAL].]

Please arrange payment by [DATE] to avoid further action. If you are experiencing financial difficulty, please contact me directly. I am open to discussing a payment arrangement.

Payment can be made at [LINK/DETAILS].

Regards,
[YOUR NAME]

Template 6: Phone Call Script (30+ Days Overdue)

Sometimes email stops working and you need to pick up the phone.

"Hi [CLIENT NAME], this is [YOUR NAME]. I am calling about Invoice #[NUMBER] for [AMOUNT]. It is now [X] days past due, and I wanted to check in directly. Is there anything I can help resolve on your end, or can I expect payment this week?"

Stay calm and professional. You are a business owner following up on a legitimate debt, so do not apologize for calling.

Template 7: Final Notice Before Collections (60 Days Overdue)

This is your last email before escalating to a collections agency or small claims court.

Subject: Final notice: Invoice #[NUMBER], [AMOUNT] past due

Dear [CLIENT NAME],

Despite multiple attempts to reach you, Invoice #[NUMBER] for [AMOUNT] (due [DATE]) remains unpaid. This is a final notice before I refer this account to a collections agency [or take legal action].

To resolve this matter, please remit payment in full by [DATE] via [PAYMENT METHOD] at [LINK/DETAILS].

If I do not receive payment or hear from you by that date, I will proceed accordingly.

Regards,
[YOUR NAME]

Tips for All Follow-Up Emails

Reference the invoice number every time. It makes the bill easy for the client, and their accounting team, to locate.

Always include the payment link or instructions. Remove every possible step between "I need to pay this" and "payment sent."

Keep a paper trail. Put all correspondence in writing. If this ends up at collections or in small claims, you will want the documentation.

Automate the early reminders. The pre-due and first follow-up notes are easy to automate with WaffleInvoice. You set it up once per client and the software sends the reminders, so the first message is not you, it is a system notification, which is a lot easier emotionally.

Create a free WaffleInvoice account to automate payment reminders and stop chasing invoices by hand.

Related reads: How to Follow Up on Late Payments · How to Handle Clients Who Don't Pay · Payment Terms for Freelancers