Mortgage Amortization Calculator
Calculate your monthly payment, total interest paid, and see a detailed year-by-year amortization schedule. Add extra payments to see how much interest you can save.
| Year | Principal Paid | Interest Paid | Remaining Balance |
|---|
How Mortgage Amortization Works
Amortization is the process of paying a loan down to zero over a fixed loan term with equal monthly payments. This calculator applies the standard formulas below, then rebuilds the schedule month by month so the numbers stay consistent with whatever loan term and extra payment you enter.
Haven't picked a loan amount yet? The home affordability calculator works backward from your income and debts to a maximum price first.
Monthly Mortgage Payment Formula
The standard amortization formula calculates your fixed monthly payment (principal and interest):
Where P is the loan amount, r is the monthly interest rate (annual rate / 12), and n is the total number of payments.
Amortization Schedule: Principal and Interest by Year
Each payment is split between interest and principal. Early payments are mostly interest; later payments are mostly principal. This table aggregates payments by year.
Extra Payments and Total Interest Paid
Any extra monthly payment goes directly toward reducing the principal. This shortens your loan term and reduces total interest paid. Even small extra payments can save thousands over the life of the loan.
Still deciding whether owning beats renting at these numbers? The rent vs buy calculator carries this same monthly payment into a full year-by-year comparison against renting.
Worked Example
A $300,000 loan at 6.5% over a 30-year term, with no extra monthly payment.
Inputs Used
- Loan Amount: $300,000
- Interest Rate: 6.5%
- Loan Term: 30 years
- Extra Monthly Payment: $0
Computed Result
- Monthly Payment (P&I): $1,896
- Total Interest: $382,633
- Total Cost: $682,633
- Payoff Time: 30 yr
- Interest Saved: —
How to Read This Result
Total interest paid isn't a fixed "good" or "bad" number on its own — it scales with the loan amount, rate, and term you enter. As a general pattern, a shorter term or an extra monthly principal payment reduces total interest paid, at the cost of a higher (or unchanged) monthly payment. In this example, $382,633 in interest is paid over the life of a $300,000 loan — more than the loan amount itself — because no extra payment is applied here, so the loan runs its full 30 yr term as scheduled. Enter an extra monthly payment above to see how much that payoff time and total interest figure can drop.
Mortgage Amortization Calculator FAQs
Does this include taxes and insurance?
No. This calculator shows principal and interest (P&I) only. Your total monthly housing payment (PITI) also includes property taxes, homeowners insurance, and possibly PMI.
Is there a penalty for extra payments?
Most conventional and FHA loans allow extra principal payments without penalty. Check your loan terms to confirm.
Fixed vs adjustable rate?
This calculator assumes a fixed interest rate for the entire term. Adjustable-rate mortgages (ARMs) may start with a lower rate that changes after an initial period.
How much can extra payments save me?
Try entering $100 or $200 as an extra payment to see the impact. On a $300,000 loan at 6.5%, an extra $200/month saves over $80,000 in interest and shortens the loan by about 6 years.