Note: this tool provides a general, informational estimate based on the figures you enter. Confirm the final amount against your own records before including it in a letter you actually send.
What this tool actually does
Most people default to demanding whatever the original invoice or loan amount was, without considering whether they're entitled to more. This calculator helps you build a complete, defensible total — starting from the principal amount and adding anything else you may reasonably be entitled to, so the number in your letter reflects your full position rather than just the easiest figure to remember.
What you'll need to use it
- The original amount owed — the invoice, loan, or agreed price.
- The date the amount became due or the loss occurred.
- Any partial payments already received, and when.
- Any other documented costs directly connected to the dispute.
Why a precise amount matters in a demand letter
A demand letter with a vague or rounded amount reads as less serious than one with a precise, itemized figure. Showing exactly how you arrived at your number — principal, plus interest, minus any payments already made — signals that you've done the work and are prepared to back up the figure if the matter proceeds further.
Start with the principal amount
The principal is the core amount actually owed — an unpaid invoice, an outstanding loan, or the documented cost of a loss. Subtract any partial payments already received so your letter demands only what's genuinely still outstanding.
Adding interest to your figure
If time has passed since the amount became due, you may be entitled to include interest in your demand — see the prejudgment interest calculator for a fuller estimate of how much may have accrued. Including this in your demand letter, rather than only the original amount, means you're not quietly giving up value you may be entitled to.
Other costs worth including
Depending on your situation, you may also be able to reasonably include other documented costs directly caused by the other party's failure to pay or perform — for example, a reasonable cost you incurred fixing a problem they caused. Keep these additions specific and documented; padding a demand with speculative or unrelated costs undermines the letter's credibility.
Rounding and how you present the number
Present your total as a precise figure rather than a round number — "$3,247.50" reads as calculated and specific, while "$3,250" or "$3,000" can read as a rough guess. Show your math briefly in the letter itself (principal, interest, less payments received) so the total is easy to follow and verify.
Feeding this number into the demand letter builder
Once you have a clear, itemized total, use the demand letter builder to turn it into a complete, professionally structured letter. See how to write an effective demand letter for the fuller reasoning behind presenting your amount clearly.
Official sources
- Courts of Justice Act, R.S.O. 1990, c. C.43 — sets the Small Claims Court’s jurisdiction and the statutory framework for pre- and post-judgment interest.
- ontario.ca: Suing Someone in Small Claims Court — the official overview, including the current monetary limit.
Frequently asked questions
Should I demand more than I'm actually owed, expecting to negotiate down?
Generally, no — a precise, accurate figure is more persuasive than an inflated one, and it protects your credibility if the matter ends up in court.
Can I include interest in a demand letter even before filing a claim?
Yes — if interest has accrued on the amount owed, including it in your demand letter is reasonable and often expected.
What if I'm not sure of the exact date the amount became due?
Use your best documented estimate — an invoice date, a due date in an agreement, or the date a loan was expected to be repaid.
Is this the same as the prejudgment interest calculator?
They're related but different in scope — the prejudgment interest calculator focuses specifically on interest, while this tool helps you build a complete demand amount including interest and other costs.