How to Write & Send a Demand Letter for an Unpaid Invoice in Canada (2026)

• Send it once the reminders stop landing: A demand letter is what you reach for after a couple of polite nudges have gone nowhere.
• It's a formal request for payment: Treat it as the written step that usually comes right before a small claims court claim.
• Be specific: Name the parties, the invoice number and amount, the work done, your prior reminders, and a firm deadline.
• Keep the tone professional: A firm, factual letter gets paid. An angry, vague one gets filed away and forgotten.
• Keep proof: Save a dated copy of exactly what you sent, plus a record showing when you mailed it.
• Small claims is the backstop: If they still don't pay, small claims court is built for this. Limits vary by province.

The invoice is months overdue and the client has gone dark. You sent the friendly reminder. Then a slightly less friendly one. Now your emails just sit there unread, and you're starting to wonder if you'll ever see the money. Stop being so polite about it. By the time a demand letter makes sense, you've usually already:

• Sent the original invoice with clear payment terms.
• Sent at least one or two reminders after the due date passed.
• Possibly followed up by phone or email and gotten silence, excuses, or broken promises.

Once the reminders go unanswered, the tone has to change. A demand letter tells the client you've moved from "just checking in" to "this is the formal step before I take further action." For a lot of late payers, that's the shift that finally shakes the money loose. Nobody wants the next stage to be a court claim.

Here's the rough rule I use. If an invoice is 30+ days overdue and at least one reminder has been ignored, it's time for a demand letter.

A demand letter is a formal written request for payment, and it's widely treated as the expected step before you start a small claims court claim. Courts and paralegals routinely tell you to send one first, so you can show you gave the other side a fair chance to settle before suing (Alberta Courts: Before You Sue).

It works on two levels:

• It changes the psychology. A printed letter that shows up in the mail lands differently than another email buried in an inbox. It reads as deliberate and serious. Harder to ignore than a ping.
• It builds your record. If you do end up in small claims court, a dated demand letter and proof you sent it is strong evidence that you tried to resolve things and spelled out exactly what was owed. A paper trail of your collection efforts is the kind of documentation that holds up a claim.

You don't need anything fancy to send it. Regular mail does the job. What matters is that you keep a dated copy of the letter and a record of when it went out.

A demand letter should leave no room for confusion. Get all of this in:

• Clear identification of both parties: Your full name or business name and address, and the recipient's name/business and address.
• The date you're sending the letter.
• The invoice details: Invoice number, date issued, original due date, and the exact amount outstanding.
• The work performed: A short, factual description of what you delivered or the services you provided.
• A record of prior reminders: Note that you previously invoiced and followed up, with dates if you have them, and that the invoice is still unpaid.
• A firm payment deadline: A specific date or number of days. Commonly 7 to 14 days from the letter.
• The consequences: State plainly that if payment isn't received by the deadline, you may commence a claim in small claims court to recover the amount owed, plus any interest and costs you're entitled to.
• A statement that this is a final demand for payment before you take further steps.
• How to pay: Make it easy. Payment method, e-transfer email, whatever it takes so there's no excuse left.

Attach or reference a copy of the original invoice while you're at it, so the amount is beyond dispute.

Firm and professional, not emotional. You want the letter to land with the client and hold up if a judge ever reads it.

Do

• Stick to facts: amounts, dates, and what was agreed.
• Keep it short and direct. One page is plenty.
• State the deadline and consequence clearly and calmly.
• Stay polite. "Please remit payment by..." does more work than a threat.

Don't

• Insult, swear, or make it personal. It undermines you and looks bad in court.
• Exaggerate or invent consequences you don't intend to follow through on.
• Be vague about the amount or the deadline.
• Bury the demand under paragraphs of backstory.

Read it back and ask whether it would sound reasonable to a neutral third party. If yes, you've got the tone right.

Here's a full template to adapt. Swap the bracketed bits for your own details and you're done.

Keep the wording factual and the deadline realistic. Got a signed contract or agreed terms? Reference them in the second paragraph.

Once the letter is ready, the practical part is getting it in front of the client and keeping evidence that you did. A mailed paper letter carries more weight than another email, and you can do the whole thing without leaving your desk. No post office trip.

With PostPal you type or upload your demand letter at postpal.ca/send. We print it, put it in an envelope, and mail it the next business day for about $6 flat. You get a dated mailing confirmation by email, so you have a record of exactly when it went out.

For your records, keep two things together:

• A dated copy of the exact letter you sent. Save the PDF you uploaded and note the date.
• Your PostPal mailing confirmation. This is your dated proof that the letter was sent.

That's your proof: a copy of what you said, plus a record of when you sent it. If the matter ever reaches small claims court, you can show you made a clear, written demand and gave the client a fair shot at paying.

If the deadline passes and you've heard nothing, small claims court is your main option. It's built for exactly this. The amounts are modest, you don't need a lawyer, and the process is simple enough for individuals and small businesses to handle on their own.

A few things to know:

• Limits vary by province. Each province and territory sets a maximum dollar amount for small claims. Ontario, for instance, raised its limit to $50,000 effective October 1, 2025 (Ontario: Suing Someone in Small Claims Court). Other provinces sit lower. Check your own province's rules before filing.
• Your demand letter helps. Bringing your dated demand letter, the original invoice, your reminders, and your mailing confirmation shows the court you communicated clearly and tried to settle first.
• There are filing fees and steps. You file a claim, the other side gets a chance to respond, and a lot of cases settle before a hearing.

More often than not, the demand letter is enough on its own. The threat of court shakes the payment loose. And if it doesn't, you'll have everything you need to take the next step.

Do I need a lawyer to send a demand letter?

No. You can write and send one yourself, and most freelancers and small-business owners do exactly that. A lawyer or paralegal can put it on letterhead for added weight, but for a straightforward unpaid invoice it isn't necessary. You don't need a lawyer to file in small claims court either, though you can hire one if you want.

How long should I give them to pay?

Most demand letters give 7 to 14 days from the date of the letter. Pick a deadline that's firm but reasonable, write it as a specific date, and stick to it. If your contract already sets a notice period, follow that instead.

Can I charge interest on a late invoice?

Yes, if your contract or invoice terms set out a late-payment interest rate. You can claim it. If you never specified a rate, default rules may apply, but what you can actually recover is often limited. Reference your agreed terms in the letter, and keep the interest claim modest and clearly calculated.

What if I never had a written contract?

You can still go after an unpaid invoice. An invoice with stated payment terms, plus emails, messages, and evidence of the work you delivered, can carry a claim even without a signed contract. Your demand letter and records matter even more in that situation.

Should I send the original invoice again with the letter?

Yes. Attaching or referencing a copy of the original invoice kills any argument about the amount owed and what it covered. It also thickens your paper trail.

What if I get a partial payment or a promise to pay?

Get any new arrangement in writing. Even a short email confirming the amount and the dates will do. If they pay part of it, acknowledge what came in and restate the remaining balance and deadline. Don't let a vague promise reset the clock forever.

How do I actually mail it?

Type or upload your letter at postpal.ca/send. PostPal prints it, envelopes it, and mails it for about $6 flat, then emails you a dated mailing confirmation. You get proof of when it went out and you never leave your desk.

You did the work. You don't have to eat the cost of it. A firm, well-written demand letter is usually the one move that gets a quiet client to pay up, and when it doesn't, you walk into small claims court already prepared. So write the letter. Set a real deadline. Mail it. Keep a dated copy and your mailing confirmation, and let the deadline do its job.

Once your letter is ready, you can have it sent in a couple of minutes with a dated record of when it went out.

Mail your demand letter with PostPal →

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