Calculate your monthly payment, total interest, and full amortization schedule for any loan.
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Enter your loan amount, annual interest rate, and loan term in years. Optionally set a start date to see exact payment dates in the schedule. Click "Calculate Amortization" (or press Enter) to instantly see your monthly payment, total cost, and a full breakdown of every payment across the life of the loan.
Use the sliders to quickly experiment with different loan amounts, rates, or terms and see how the numbers change in real time.
Most people focus only on the monthly payment when taking out a loan — but the real story is in the total interest paid. On a $300,000 mortgage at 7% for 30 years, your monthly payment is around $1,996. But by the end, you'll have paid over $418,000 — nearly $119,000 in pure interest. That's almost 40% of the total cost going to the lender, not to your home equity.
An amortization schedule shows exactly how each payment is split between principal (reducing what you owe) and interest (the lender's fee). In the early years of a loan, the majority of your payment goes to interest. For example, on that same 30-year mortgage, your first payment might be $1,750 in interest and only $246 in principal. It takes roughly 19 years before the split flips in your favor.
Understanding this helps you make smarter decisions: whether to make extra payments early, refinance when rates drop, or choose a 15-year term over 30. Even a single extra payment per year can save tens of thousands of dollars and cut years off a mortgage.
The standard amortization formula calculates a fixed monthly payment that covers both interest and principal across the full loan term:
Where: M = monthly payment, P = principal (loan amount), r = monthly interest rate (annual rate ÷ 12), n = total number of payments (years × 12).
Each month, the interest portion = remaining balance × monthly rate. The principal portion = M − interest. The balance decreases by the principal portion each month, which means interest charges shrink slightly each period — that's why the principal share grows over time.
An amortization schedule is a complete table of every loan payment, showing how much goes to principal, how much to interest, and the remaining balance after each payment. It reveals that early payments are mostly interest, while later payments are mostly principal.
The most effective strategies are: making bi-weekly payments instead of monthly (you make 26 half-payments = 13 full payments per year), applying any windfalls directly to principal, or refinancing to a shorter term when rates are favorable. Even an extra $100/month on a typical 30-year mortgage can knock 4–5 years off the loan.
In early months, your outstanding balance is at its highest, so the interest charged each payment is also at its highest. Since your monthly payment is fixed, that leaves less room for principal reduction. As the balance shrinks, the interest portion falls and your principal paydown accelerates — this is the "hockey stick" effect in amortization.
Yes — the same amortization formula applies to any fixed-rate installment loan: mortgages, auto loans, personal loans, student loans, and home equity loans. Just enter the loan amount, rate, and term. The only difference is that mortgages may have additional costs like PMI and escrow not included here.