A walkthrough, end to end.
- 1
Enter the loan amount, annual rate and term in years.
- 2
The calculator builds a full month-by-month amortization schedule, condensed to a yearly summary.
- 3
See exactly how much of each year's payments goes to interest vs. principal — and how the ratio flips over time.
Amortization schedule
Each month: interest = balance × monthly rate; principal = payment − interest; balance reduces by principal. Early in the loan, most of each payment is interest. Crossover (when principal exceeds interest) typically happens around the 40–60% mark of the term, depending on rate.
What you can do with this.
Mortgage amortization schedule
30-year mortgages start with ~80% interest in the first year, dropping to ~10% interest in the final year. Use the schedule to see exactly when your home is 'half paid off'.
Auto loan amortization
5–7 year auto loans have flatter interest curves than mortgages — the principal/interest split crossover happens early. Worth knowing if you're considering refinancing.
Student loan amortization
Standard 10-year repayment schedules have ~50/50 interest split for the first 3–4 years. Income-driven plans extend the term and dramatically increase total interest.
Extra principal payments — impact
Adding $200/mo to a 30-year mortgage shaves ~5 years off the term and saves significant interest. Run two schedules and compare to find the leverage.
Biweekly payments
Paying half your monthly payment every two weeks results in 26 half-payments per year = 13 monthly equivalents. Saves ~7 years on a 30-year mortgage with no per-payment increase.
Loan refinance comparison
Build the schedule for your current loan and the proposed new one. Compare total interest remaining; subtract closing costs from the savings to find true breakeven.
Prepayment penalty analysis
Some loans charge for paying off early. The schedule helps quantify the interest you'd save vs. the prepayment penalty cost.
Amortization calculator 2026 — what's current
Modern lender portals now show interactive schedules. Use this calculator independently to confirm the lender's math, especially when refinancing or shopping rates.
Frequently asked.
Interest is charged on the outstanding balance. Early in the loan, the balance is highest, so interest is highest. As principal pays down, less interest accrues, more goes to principal.
Roughly at the 40–60% mark of the term, depending on rate. Higher rates push the crossover later. The yearly schedule shows exactly when it happens for your loan.
Every extra dollar of principal saves interest at the loan's rate for every remaining month. A $1,000 extra payment in year 1 of a 30-year 7% loan saves ~$2,400 in interest by year 30.
No. Calculations run entirely in your browser.