The calculations are based on the Canadian regulations for a conventional semi-annually compounded mortgage.
If you live in Canada and are considering buying a property there, you have to use this calculator, as Canadian regulations about mortgages differ from those in the USA.
If the property you are interested in costs 300,000.00 Canadian dollars and the loan you are going to take out is for $250,000.00 at a 5.000% interest rate for 30 years, you will be required to make a $75,000.00 down payment (the required down payment is 25% of a property's list price for homes with prices below $400,000 and 35% if property costs more than that value).
This means your monthly payment (principal and interest only) will be $1,334.23. By the end of the mortgage term, your total payments will amount to $480,316.13, $230,321.61 of which is the interest.