Published by Beaver Ledger · Edited
The calculator assumes one fixed rate, compounded twice a year, for the whole amortization. Your mortgage contract decides the real terms.
The question
What does a mortgage payment actually pay for?
Each payment covers that period's interest, and the rest pays down what you borrowed. How much you pay depends on the balance, how the rate is compounded, how often you pay and the amortization. The rate alone doesn't tell you the payment.
Know your numbers
Principal is the amount you borrow, usually the home price minus your down payment. Amortization is how long it would take to pay off the whole loan; the term is how long your current contract lasts. A payment estimate doesn't include all the costs of owning a home.
Example: how the rate becomes a payment
Say you borrow $400,000 at 5%, compounded twice a year, over 25 years with monthly payments. The monthly rate is (1 + 0.05 ÷ 2)^(1 ÷ 6) − 1. Spreading the loan over 300 monthly payments gives about $2,326.42 a month.
That's an illustration, not a lender's offer. It leaves out insurance, fees, property tax and future rate changes, and a contract that compounds differently would give a different payment.
Regular and accelerated payments
In the calculator, regular bi-weekly payments are a year of monthly payments divided by 26. Accelerated bi-weekly payments are half the monthly payment, 26 times a year, which adds up to 13 monthly payments. In the example above, that's about $1,163.21 every two weeks. You pay more each year, so the loan is paid off sooner.
Look at the whole loan
Look at the total interest and how payments fit your cash flow, not just the payment size. Your contract decides whether you can pay extra and what penalties apply, so check it before planning an accelerated schedule or lump sums.
- Confirm the amount, how the rate is compounded and how often you pay.
- Budget for the costs of owning a home on top of the payment.
- Run the numbers again when your term renews.
Sources checked for this editorial revision on October 3, 2026. Educational content from Beaver Ledger; no professional review is claimed. Methods and limitations · Editorial practices and corrections.