Guides · reviewed 2026-09-04

Unpaid invoice: how to sue for it in Small Claims Court

Legal information, not legal advice. Results depend on the facts of your case.

Legal information, not legal advice. This guide and our free tools give legal information. They do not give advice about your case. A licensed lawyer can give legal advice.

The answer

An unpaid invoice is a debt. You can sue for it in Small Claims Court, up to $50,000. An invoice claim is a claim for a fixed amount. If the customer files no Defence, the clerk can sign a default judgment without a trial.

What to do

  1. Collect the documents: the invoice, the contract or purchase order, delivery proof, and emails.
  2. Check the deadline: /calculators/deadlines. In most cases, the 2-year clock starts when the payment was due and did not come.
  3. Add interest. Use the contract rate if the customer agreed to one. If not, use the Courts of Justice Act rate.
  4. Send a demand letter with the invoice attached: /demand-letter.
  5. Confirm the customer's exact legal name. Read: name the right defendant.
  6. Fill in and file Form 7A, and pay $108: /build/7a.
  7. Serve the claim within 6 months. File Form 8A.
  8. No Defence after 20 days? Ask the clerk to note default, then request a default judgment: $94.

Interest on invoices

A rate printed on an invoice does not always bind the customer. The rate must be a term the customer agreed to. With no agreed rate, claim the court rate: 2.5% for a case started in any quarter of 2026.

Deadlines and fees

  • Start within 2 years, in most cases.
  • File a claim: $108. Fix a trial date in a defended case: $308.
  • Default judgment request: $94.
  • 10 or more claims already filed in the same office in one calendar year? Each new claim costs $228. Read: the 10-claim fee rule.

Common mistakes

  • Do not let old invoices sit. The 2-year clock runs on each unpaid invoice.
  • Do not sue the store name. Sue the legal entity behind it.
  • Do not leave the interest section of Form 7A empty.
  • You can put several unpaid invoices from one customer into one claim. Do not split one claim into 2 claims to fit under $50,000.
  • A part payment or a signed written acknowledgment of the debt restarts the 2-year clock. Keep the records.

When to get a lawyer

Get legal advice if the customer disputes the goods or the work. Legal services provided by Mithril Law — Jonathan Kleiman, licensed Ontario lawyer.

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