How to write a demand letter for unpaid invoices (with free template)

A quick note, InvoiceRecover is not an attorney or a law firm and can only provide self-help information. This post is not legal advice, and you should consult with your lawyer before taking any legal action. 

Easy button (TL;DR): Use our free demand letter generator. Easily create a formal letter demanding payment for your outstanding invoice and download or send it today.

Maybe you've hit a brick wall with an unpaid invoice? You've sent the follow-ups, made the phone calls, and chased your customer for months. But nothing seems to work. 

It's probably time to send a formal demand for payment letter or demand letter for short. 

What is a demand letter? 

A demand letter is a formal letter demanding payment for an unpaid invoice. A demand letter can be used as evidence that you communicated the outstanding payment, provided all the relevant information, and allowed your customer to pay the invoice and rectify the situation. A demand letter is usually delivered by email, physical mail, or even certified mail to ensure its receipt. 

A demand letter often includes the following information, and we'll walk you through you precisely what you need for each of these sections:

  1. Customer contact information
  2. Invoice details
  3. A formal demand for payment
  4. Consequences of inaction or failure to pay
  5. Your contact information, signature, and date sent

Remember, a demand letter is simple to write. Your demand letter does not need to be complicated or lengthy. Don't overthink it. Keep it short and straightforward. 

You can use the rest of this post as a guide or use our free demand letter generator. Now, let's break down each section needed to create a demand for payment letter.

Your customer's contact information

The first thing to include in your demand letter is your customer's contact information. Including the customer information clarifies who the intended recipient is and how you've contacted them in the past. The most common details are full name, company name, email address, and phone number. Optionally, you may want to have the physical address if you send the demand letter via postal mail. 

The unpaid invoice details

Next, you want to include all the information about the unpaid invoice itself. Invoice number, due date, and amount due are the most important. In addition, you may want to include a written description of the services you provided or attach a copy of the invoice to the demand letter to be thorough. 

The formal demand for payment

The formal demand for payment is the essential part of the demand letter. This section is where you make it clear that this is a serious demand. Now is your chance to ratchet up the pressure and let your customer know you mean business. 

The formal demand section can feel a bit harsh—however, it is essential to use strong language here. Your customer needs to know this is not just another reminder email, and they need to treat it accordingly.  

A few examples of standard demand letter language are: 


Consequences of inaction or failure to pay

Our demand letter needs to communicate what will happen if our customer chooses to take no action or fails to pay their invoice. Typical consequences include:

  • Transferring debt to a collection agency (like InvoiceRecover).
  • Taking further legal action such as small claims court.
  • Reporting your customer to a credit reporting agency.
  • Additional fees for late payment or assignment of legal fees. 

If you are unsure what your next steps will be, it is still vital to explain that there will be consequences. However, you can keep the specific outcomes vague.

We know what you're thinking, is this a threat? And the answer is yes, it is. However, we're not looking to be harsh or overly threatening. It is a fundamental part of business; failing to pay your invoices has consequences. We are merely surfacing them up and making customers aware of them. 

Here are a couple of examples of consequences to include in your demand letter:


Your contact information, signature, and date sent

You must include your contact information as part of the demand letter. Including it ensures you give your client a means to get in touch with you to resolve the matter. 

Without contact information, your client can say they didn't know how to contact you. 

All you need to include are your full name, your company name, your email address, and your phone number. Additionally, you can list your physical address if delivering by mail or wanting a formal written response. 

Finally, your signature and the date are the last two pieces to include. The signature is crucial as it increases the formality of the demand letter. And the date sent acts to create a point in time that you can use in further legal action if necessary. 

Putting it all together

Now that you know what goes in a formal demand letter, you can put it all together and create your own. Remember that you can customize this letter to suit your needs, but don't overcomplicate it. 

And, good luck! We hope this helps get you paid.

Download our free template or use our free demand letter generator


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Freelance Designer