How to write a demand letter for an unpaid invoice
Key takeaways
One page. Six parts. No adjectives about the customer.
Give a calendar date, not "soon". 10 to 14 days is common.
Name one next step you will actually take, such as filing in small claims.
Write it for the judge as much as the customer. It may become Exhibit A.
What are the steps to write a demand letter?
Gather the paperwork first, then write. The letter takes 20 minutes once the facts are in front of you.
- Pull the facts. Invoice number and date, due date, amount, what the work was, and every reminder you sent with its date.
- Check the contract. Note any late fee or interest clause. Only add charges the contract allows.
- Write the six parts. Who and what, amount, history, deadline, how to pay, next step. Use the template below.
- Read it as a judge would. Cut anything emotional. Every sentence should be a fact or a request.
- Send it two ways. Email for speed, certified mail with return receipt for proof. Keep both copies.
- Diary the deadline. On the day after, follow through. See how to file small claims.
Is there a demand letter template I can copy?
Yes. Fill in the brackets and delete anything that does not apply. When to use it: the invoice is 30 or more days past due and reminders have gone unanswered.
[Your business name]
[Address] · [Email] · [Phone]
[Date]
[Customer legal name]
[Address]
Re: Final demand for payment of invoice [number]
On [date] we invoiced you $[amount] for [short description of work], due on [due date]. We sent reminders on [dates]. The invoice remains unpaid.
Please pay $[amount] by [calendar date, 10 to 14 days from today]. You can pay by [payment link, bank details or mailing address].
If we do not receive payment by that date, we intend to file a claim in [county] small claims court for the amount owed plus court costs, without further notice.
If you believe this amount is wrong, reply in writing before that date with the reason.
[Name], [Title]
[Business name]
Prefer a form? The free demand letter builder asks a few questions and writes this for you.
What tone should a demand letter use?
Firm, short and polite. You are not trying to win an argument in the letter. You are making payment the easiest option. Compare:
| Instead of | Write |
|---|---|
| "You have ignored us for months." | "We sent reminders on March 4 and March 18." |
| "Pay immediately or else." | "Please pay by April 12." |
| "We will take every action available." | "We intend to file in Harris County small claims court." |
| "This is completely unacceptable." | (Leave it out.) |
How much time should the customer get?
10 to 14 days is common and reads as fair. In Texas, if you later hire a lawyer and want to recover attorney's fees on a services or contract claim, the claim must have been presented and left unpaid for 30 days (Tex. Civ. Prac. & Rem. Code 38.002), so some Texas businesses give 30 days to keep that option open.
Should I include interest and late fees?
Only if the contract, accepted quote or invoice terms say so, and show the arithmetic. Adding a fee you cannot point to in writing gives the customer something to dispute and makes the whole letter look less reliable.
Want it written and sent for you?
Our demand letter service writes the letter from your invoice, sends it by email and certified mail and follows up. It is $99 to start, with no cut of what you recover. Not sure what a demand letter does? Start with what a demand letter is.
Last updated October 2026. Easy Small Claims is not a law firm and this page is general information, not legal advice.
Questions, answered
How do I write a demand letter for money owed?
Open with your business name and the invoice number, then state the exact amount and what it was for. List the invoice date, due date and the reminders you sent. Set a calendar date to pay by, explain how to pay, and name the step you will take if the money does not arrive. Sign it and keep a copy.
Can I write a demand letter myself?
Yes. Most demand letters for unpaid invoices are written by the business owner. There is no required legal form. What matters is that it is accurate, calm and specific about the amount, the deadline and the next step. A free builder or a template saves time and helps you avoid leaving out a part.
What should you not say in a demand letter?
Avoid insults, guesses about the customer's motives and threats you will not carry out. Never threaten criminal charges, reporting to authorities or public posts to force payment. Do not overstate the amount or add fees your contract does not allow. A judge may read every line, so write as if one will.
How long should a demand letter be?
One page is right for nearly every unpaid invoice. Long letters bury the amount and the deadline, which are the two things the customer needs to see. Put the supporting detail in attachments: the invoice, the contract or accepted quote, and copies of earlier reminders.
A small business owner himself, Nitin has been on the wrong end of an unpaid invoice and knows how easy it is to give up on one. He built Easy Small Claims so owners can get that money back. He is also a practicing barrister.