Because the Interest Act and Criminal Code are federal, the interest and criminal-rate rules described above apply identically in every common-law province. What changes province to province is the contract and limitations layer, and that layer decides whether a lender can still sue.
Ontario applies a basic two-year limitation period under the Limitations Act, 2002, running from the day the claim was discovered, which for a missed instalment is usually the day payment was due. A demand loan with no fixed schedule can start the clock on the day the loan is made under Ontario's rules, so lenders relying on "payable on demand" language should understand the clock may already be running. A written acknowledgement of the debt or a part payment can reset that period, which is one reason formalising an old loan is worthwhile.
British Columbia also uses a two-year basic limitation under its Limitation Act, with a fifteen-year ultimate long-stop. BC's treatment of demand obligations was deliberately reformed so that the limitation period for a demand debt generally runs from the first day after demand is made, which gives lenders more room than the Ontario position. The province's consumer and contract rules otherwise track common-law principles.
Alberta sets a two-year discovery period alongside a ten-year ultimate limitation under its Limitations Act, and courts there give real weight to written acknowledgements as a means of restarting time. A signed repayment agreement with a dated schedule creates exactly the paper trail Alberta courts look for when a lender needs to show the debt is live and quantified.
The one province this template does not serve is Quebec, where lending between individuals is governed by the Civil Code of Québec rather than the common law, with its own rules on interest, prescription and proof. A borrower or lender in Quebec needs a document drafted to the civil-law regime. For employment-linked advances documented alongside a job, our employment agreement template for Canada covers the related paperwork.