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How to follow up on an unpaid invoice

Monkee · September 27, 2026

Follow up on an unpaid invoice with three short emails: a friendly reminder 7 days after the due date, a firm nudge at 14 days, and a final notice at 30 days. Each email restates the invoice number, the amount, and the due date, and each one makes paying the easiest possible action. Most late invoices get paid at the first or second email. The sequence works because it is predictable, polite, and impossible to misunderstand.

Why the 7 / 14 / 30 cadence works

Late payment is usually forgetfulness, not malice. The day 7 email assumes the invoice slipped through the cracks and gives the client an easy save. The day 14 email signals that you are tracking this and it is now a real overdue balance. The day 30 email draws the line and names the consequence. Escalating the tone in three steps keeps the relationship intact for the clients worth keeping, and it creates a paper trail for the ones who are not.

Count from the due date, not the send date. If your terms are Net 14 and you sent the invoice on the 1st, day 7 of the sequence is the 22nd. Saying "7 days overdue" when your own terms gave them 30 days makes you look disorganized.

Day 7: the friendly reminder

Assume good intent. Short, warm, and specific. Attach the invoice again even if you already sent it, because the most common reason for non-payment is that the original email is buried.

Day 14: the firm nudge

Drop the warmth, keep the professionalism. Name the number of days overdue, restate the amount, and ask for a specific payment date. Vague asks get vague responses.

Day 30: the final notice

This is the last friendly email. State plainly that this is the final notice, name the late fee if your terms include one, and say what happens next: paused work, collections, or both. Send it, then act on whatever you said.

Attach the invoice every single time

Every follow-up carries a fresh copy of the invoice as a PDF. This removes the two most common excuses in one move: "I never got it" and "I can't find it." It also means the client never has to dig through old email to pay you. Each email should be payable in under a minute from a phone: invoice attached, payment details on the invoice, one clear amount.

What not to do

• Do not apologize for asking. "Sorry to bother you" trains clients to treat your invoice as optional. You did the work; the reminder is business.
• Do not threaten what you will not do. If you say you will pause work or send to collections, mean it. Empty threats teach clients that your deadlines are decorative.
• Do not keep working for free. Starting the next milestone while the last invoice is 30 days overdue tells the client that non-payment has no consequences.
• Do not make it personal. Stick to invoice numbers, amounts, and dates. The moment the email sounds angry, the client stops reading it as a bill and starts reading it as a fight.

Make the follow-up write itself

The whole sequence gets easier when the invoice already carries your payment terms, your late fee wording, and every payment method you accept. MonkeeTools' invoice generator puts your terms on the invoice itself, so the day 7 email is just "per the terms on the attached invoice" instead of a negotiation. When the terms are printed, the follow-up is a reminder. When they are not, every late invoice becomes an argument about what was agreed.

See it done: a working example

This link loads a complete example invoice into the generator, terms included. Free, no signup, editable the moment it opens:

Open the example invoice

Put your terms on it once, and every follow-up email you ever send gets shorter.

A follow-up is not a confrontation. It is three short emails, each one clearer than the last, each one making payment the easiest action.

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