An amortization schedule is the month-by-month story of your mortgage: how much of each payment kills interest versus principal, and how the balance shrinks. Once you can read it, extra-payment strategies stop being mysterious.
Your payment is split two ways
Every mortgage payment is the same total amount, but it's divided between interest (the lender's fee on your remaining balance) and principal (the actual loan being paid down). The schedule shows that split for every single payment.
Read one row before you try to read the whole table
A schedule looks intimidating because it has 300 or 360 rows. But every row is built from the same two lines of arithmetic, and once you've done them once by hand the rest of the table is just repetition.
Suppose — purely as an illustration — a balance of $300,000 at a nominal 5% with monthly compounding, and a fixed payment of $1,750.
- Interest for the month is the balance times the monthly rate: $300,000 × (5% ÷ 12) = $1,250.
- Principal is whatever's left of the payment: $1,750 − $1,250 = $500.
- New balance is the old balance minus that principal: $300,000 − $500 = $299,500.
Now do it again. The next month's interest is charged on $299,500, so it's $1,247.92 — two dollars less. Principal is $502.08 — two dollars more. That tiny shift is the whole engine of the schedule. It's imperceptible month to month and enormous over 25 years, because each extra dollar of principal permanently reduces the base that all future interest is charged on.
Why early payments feel like they do nothing
At the start, your balance is large, so most of each payment goes to interest and only a sliver to principal. This is normal — not a scam. As the balance falls, the interest portion shrinks and the principal portion grows, so the back half of your term pays the loan down much faster.
The columns you'll see
| Column | What it tells you |
|---|---|
| Payment # | Which month you're looking at |
| Payment | Your fixed total payment |
| Interest | The lender's portion this month |
| Principal | How much loan you actually retired |
| Balance | What you still owe afterward |
Finding the crossover row
The one row worth hunting for is the crossover: the first month where the principal column finally exceeds the interest column. Before it, the bank is getting more of your money than your equity is. After it, the balance starts falling in a way you can actually see on the statement.
Where that row lands depends almost entirely on your interest rate, not on how big the loan is. Double the loan and the crossover barely moves. Raise the rate and it moves dramatically later, because a higher rate means more of every fixed payment is consumed before any principal gets touched. It's the cleanest way to feel what a rate difference is really worth — scroll the schedule at your current rate, note the crossover row, then re-run it a percentage point lower and watch how many years earlier it arrives.
What extra payments really do
An extra payment goes straight to principal. Because future interest is charged on a smaller balance, a single extra payment early on saves interest on every month that follows — often several dollars of interest for each extra dollar of principal, and it can shave years off the term.
Three details decide how much you actually get out of this:
- Timing beats size. A lump sum in year two is working for you for 23 more years. The identical sum in year twenty has almost nothing left to save. If you're going to prepay at all, prepaying early is where the leverage is.
- It has to be applied to principal. Some lenders will treat an unlabelled extra transfer as a prepaid regular instalment, which does nothing for you. Say explicitly that it's a principal prepayment.
- The payment doesn't shrink — the term does. On most fixed mortgages, prepaying leaves your monthly amount unchanged and simply ends the schedule sooner. If you wanted a smaller monthly payment instead, that's a different request (a recast or re-amortization) and not every lender offers it.
Accelerated bi-weekly payments work the same way in disguise. Paying half your monthly amount every two weeks produces 26 half-payments a year, which is 13 monthly payments rather than 12. The extra one is an annual principal prepayment you never have to remember to make.
Two things that make a Canadian schedule look different
If you're comparing a Canadian schedule with an American one, two structural differences explain most of the confusion.
Compounding. Canadian fixed-rate mortgages are conventionally compounded semi-annually, while US fixed-rate mortgages are compounded monthly. That means the same posted rate produces a slightly different payment and a slightly different interest column on each side of the border. Your schedule isn't wrong; the convention behind it is different.
Term versus amortization. In Canada the amortization is how long the loan takes to disappear — often 25 years — but the term is the contract you actually signed, commonly five years. Everything in the schedule past the end of your term is a projection at today's rate, not a commitment. At renewal the rate resets, the payment is recalculated on the balance and time remaining, and a fresh schedule begins. US borrowers with a 30-year fixed usually have a schedule that is binding for its whole length.
Where the schedule won't match your bank statement
People often assume their schedule is broken when it doesn't reconcile to the cent. Usually it's one of these.
- The first payment is odd. Interest often accrues from the funding date, so the first instalment may cover a partial or extended period and won't fit the pattern of the rows after it.
- It only shows the loan. Property tax, home insurance, condo or HOA fees, and mortgage default insurance premiums are not in the schedule. In the US these are frequently bundled into one escrowed payment (the "PITI" figure), so the amount leaving your account is bigger than the schedule's payment column.
- Rounding. The payment is normally rounded to the cent, and the accumulated difference is absorbed by a slightly different final payment.
- Prepayments apply on a date, not instantly. Money sitting with the lender until the next scheduled payment date isn't reducing interest yet.
- Prepayment privileges have limits. Many Canadian closed mortgages cap how much you can prepay each year without a penalty. Check yours before planning a large lump sum.
Questions a schedule can answer that a monthly payment can't
Once you can read it, the schedule stops being a document and becomes a decision tool. Use it to check: how much you'd still owe if you sold in year seven; how much total interest a 30-year term costs versus a 25-year one on the same loan; whether the up-front cost of refinancing is recovered by the interest saved before you'd likely move; and how much equity you'll actually have built by a given date, as opposed to how much you feel like you've paid off.
See your own schedule
Our mortgage calculators generate a full amortization schedule and show total interest, so you can test what an extra payment or a shorter term would save you.
This article is general information, not financial, tax, or medical advice. See our disclaimer.