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    Work out what a late-paying client actually owes you in interest.

    For sole proprietors and small firms staring at an overdue invoice. Applies your contract's interest rate to the days overdue.

    Sound familiar?

    • “A client's sitting on your invoice and you don't know what you can actually charge them”
    • “You're not sure if you're even allowed to add interest”
    • “You want to send a demand that has teeth”

    What this tool does

    Calculates simple interest on an overdue invoice using the annual interest rate set by your contract (defaults to 18% per year, the common 1.5% per month term), based on the days between the due date and the date paid.

    Defaults to today's date.

    Defaults to 18% per year (1.5% per month) - the common contractual term. Change it to match your contract.

    What the law actually says

    • Canada has no single statutory late-payment interest rate. Interest on an overdue invoice is whatever your contract specifies - a common term is 1.5% per month (18% per year). If your contract is silent, you can still claim prejudgment interest at the rate set by your province's courts.
    • In the federal sector and the provinces with prompt-payment laws in force (Ontario, federal, Saskatchewan, Alberta, Manitoba, NWT), there are also strict payment deadlines and a fast adjudication process to force payment - often quicker than court.

    What to do next