Say your mortgage is 300,000 and rate 5%. You would pay 15,000 in interest. Subtract from your total yearly payment say 25,000. You pay back 10,000 a year divide by 12 for months or payment period to get the amount.
It may not be authoritative but you can start with https://laws-lois.justice.gc.ca/eng/acts/i-15/page-1.html which should be.
First, they renew their interest rates every 5 years over a 20-30-40 mortgage. Think of it as mandatory refinancing.
Unlike the US where a homeowner can lock in a low interest rate for a very long time.
The U.S. is an anomaly with these loans. Most countries don't do this 30 year fixed low rate mortgages like the U.S. It simply doesn't make sense for lenders to underwrite long loans at low rates.
As 2008 taught us, other ways can come up to try and make money.
Variable rate mortgages were a better bet 88% of the time between 1950 and 2000:
* https://wowa.ca/static/fixed-vs-variable-study.pdf
Post-2000 variable did fairly well as well.
It's the recency bias of the last 1-2 years that have people really freaking out about it.
Typically, you decide on how you are going to approach the interest rate, and for how long. Owners can lock in for a fixed interest rate, or a variable rate that changes with prime. Term is most often 5 years, but latesly shorter or more flexible mortgages are more popular, sometimes between 2-4 years, and some folks who might take a risk on a 5+ year mortgage rate.
The variable rate mortgages out performed fixed rate mortgages for nearly 15-20 years. The tables turned in the past year or two.
during the re-up you can throw down extra money, but that's because it's an open contract, essentially.