How is mortgage in Canada calculated?

I'm taking a finance course at a Canadian university. The teacher said this time-of-money is how the banks calculate their loans and mortgages. Out of the blue, I want to try how close the formula in school match up to the real world. Here's my scenario:

Borrow \$300,000 at 3% interest, to be paid over 25 years. By law, the interest is compounded twice per year. Payment is to be made bi-weekly (26 payments per year). How much is the bi-weekly payment?

My calculation

I first calculate the periodic interest rate:

r = (1 + 0.03 / 2) ^ (2/26) - 1 = 0.001145934...

Then plug everything into Excel:

=PMT(r, 650, 300000)

The result is \$654.83.

Bank's calculation

I then go to TD Bank's mortgage calculator and plug in the parameters. The result is \$652.90 (see pics below). Question

How did the bank come up with their number? What did I do wrong?

• There are slightly more than 26 bi-weekly periods in a year. 26 * 14 = 364. Jan 5 '20 at 19:14
• @Nayuki Sounds like an answer to me. Jan 6 '20 at 18:35