Amortization Calculator
See your monthly payment and exactly how each one splits between interest and principal over the life of the loan.
Your loan
Works for any fixed-rate loan: mortgage, auto, personal, student
The total amount borrowed.
The loan's fixed annual interest rate.
How many years to pay it off.
Your payment
Monthly payment and total cost
Monthly payment
$1,896.2
Total interest paid
$382,633.47
Total paid over loan
$682,633.47
Interest as a share of total paid
56%
Remaining balance over time
How the loan pays down month by month
Why Early Payments Are Mostly Interest
For example, a $300,000 loan at 6.5% over 30 years runs about $1,896.2 a month, with total interest over the life of the loan close to $382,633.47, more than the amount borrowed. Amortization means each payment is split between interest, calculated on the remaining balance, and principal, which actually reduces what's owed. Early on, the balance is largest, so interest takes the biggest bite of each payment; as the balance shrinks, more of each payment goes toward principal instead. This is why an extra payment made early in a loan does more to shorten it than the same extra payment made later.
How this is calculated
It splits every payment on a fixed-rate loan into interest (on the remaining balance) and principal (which pays the loan down).
Monthly payment = loan amount × monthly rate ÷ (1 − (1 + monthly rate) raised to the power of −number of payments). Each month, that month's interest is the remaining balance × the monthly rate; the rest of the payment reduces principal, so the balance shrinks and next month's interest is smaller.
What it assumes
- The interest rate is fixed for the full term — variable-rate loans will differ.
- Payments are made on schedule every month with no skips or extra payments.
- No taxes, insurance, or fees are included — this is principal and interest only.
Frequently asked questions
Why does so little of an early payment go toward principal?
Interest is charged on the remaining balance, which is largest at the very start of the loan, so the biggest share of each early payment covers that interest. As the balance shrinks over time, less of each payment goes to interest and more goes to principal, even though the total payment stays the same.
Does an extra payment save more money early or late in a loan?
Early. An extra payment made early reduces the balance while it's still large, cutting interest for every remaining month of the loan. The same extra payment made near the end saves far less, since there's less remaining term left for a lower balance to matter.
Is this the same as a mortgage calculator?
The core math is the same, but this calculator is loan-type agnostic: no property taxes, insurance, or PMI. For a home loan specifically, including those extra housing costs, use the dedicated mortgage calculator instead.
Results are estimates for educational purposes only, based on the values you enter and a constant rate of return. Real markets rise and fall, so your actual results will differ. This is not financial advice.