CALCULATOR TOOLS
Amortization Calculator
Loan amortization schedule by month and year, with extra payments, interest saved and a balance chart.
Calculated in your browser – nothing you enter is sent or stored.
An amortization calculator shows how a fixed-rate loan is paid off one payment at a time: how much of each payment is interest, how much goes to principal and what you still owe afterward. Use it for a mortgage, car loan, personal loan or any loan with equal monthly payments, and add extra payments to see how much sooner you are debt-free.
How to Use the Amortization Calculator
- Enter the loan amount, the yearly interest rate and the term in years (add months for terms like 5½ years).
- Pick the month of your first payment so the schedule shows real dates.
- Optionally add an extra payment every month, once a year or as a one-time lump sum.
- Switch the schedule between yearly and monthly rows, then download it as CSV or print it.
The Amortization Formula
The monthly payment is M = P × r ÷ [1 − (1 + r)−n], where P is the loan amount, r the yearly rate divided by 12 and n the number of payments. Each month the lender charges interest on the remaining balance (balance × r); whatever is left of your payment reduces the principal.
Example: a $250,000 loan at 6.5% for 30 years has a payment of $1,580.17. In the first month the interest is $250,000 × 0.065 ÷ 12 = $1,354.17 – 86% of the payment – so only $226 pays down the loan. Over the whole first year you repay just $2,794 of principal. You pay $318,861 in interest over 30 years, more than the amount borrowed, and the balance doesn't fall below half until payment 257, more than 21 years in.
Why Early Payments Are Mostly Interest
Because interest is charged on what you still owe, it is highest at the start and shrinks as the balance falls. The payment stays the same, so the principal portion grows every month. The chart under the calculator shows this "crossover": the interest line flattens while the principal line climbs. It is also why paying extra early in a loan saves the most.
How Extra Payments Change the Schedule
Extra money goes straight to principal, which cuts the interest charged in every later month. For the same $250,000 loan:
| Plan | Monthly payment | Paid off in | Total interest |
|---|---|---|---|
| 30 years, no extra | $1,580.17 | 30 years | $318,861 |
| 30 years + $200 a month | $1,780.17 | 22 yrs 1 mo | $221,243 |
| 15-year loan | $2,177.77 | 15 years | $141,998 |
An extra $200 a month saves $97,618 and almost 8 years. Before you pay extra, make sure your loan has no prepayment penalty and ask the lender to apply the money to principal, not to next month's payment.
Amortized vs Other Loans
- Fully amortizing (most mortgages, car and personal loans): equal payments that reach a zero balance on the last one.
- Interest-only (some HELOCs, during the draw period): payments cover only interest, so the balance does not fall – see the HELOC calculator.
- Credit cards are not amortized: the minimum changes with the balance. Use the credit card payoff calculator instead.
Sources
- CFPB – Buying a house: tools and resources
- CFPB – What is a prepayment penalty?
- Freddie Mac – Primary Mortgage Market Survey (current rates)
Last reviewed: October 2026 by the ShrinkBee team. Results are estimates for planning and education, not financial, tax, legal or medical advice.
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