How to use this calculator
- Loan amount: what you’re borrowing, not the home price. For a mortgage, that’s the price minus your down payment.
- Interest rate: the note rate on your loan (not the APR, which also includes fees).
- Loan term: the number of years, usually 30 or 15 for a mortgage.
- First payment date: sets the dates in the schedule. Only the month and year are used.
- Open Extra payments to add a fixed amount every month, once a year, or a one-time lump sum with a chosen payment number.
The results show your principal-and-interest payment, how the total you’ll pay splits between principal and interest, a balance chart and a column chart of principal versus interest each year. The full schedule is below, with a CSV download.
The amortization formula
A fixed-rate loan’s monthly payment comes from this formula:
- M is the monthly payment (principal and interest)
- P is the loan amount
- r is the monthly rate: the annual rate ÷ 12 (6.5% → 0.0054167)
- n is the number of payments: years × 12
Each month, the calculator then works out the schedule line by line:
- Interest = current balance × r, rounded to the cent.
- Principal = payment − interest.
- New balance = old balance − principal − any extra payment.
The last payment is adjusted by a few cents so the balance lands exactly on zero.
Worked example
Take a $320,000 loan at 6.5% for 30 years. The monthly rate is 0.065 ÷ 12 and there are 360 payments, so the formula gives a payment of $2,022.62.
- Payment 1: interest is $320,000 × 0.065 ÷ 12 = $1,733.33, so only $289.29 goes to principal. The balance falls to $319,710.71.
- Over the first year you pay $20,695 of interest and $3,577 of principal: about 85% of what you pay goes to interest.
- The balance doesn’t drop below half the original loan until payment 257, more than 21 years in.
- Over the full term you pay $408,141 in interest, for a total of $728,141.
That slow start is why the balance chart curves: it falls gently at first and steeply near the end.
How the split changes over time
Here is the same $320,000 loan at 6.5%, year by year:
| Loan year | Principal paid | Interest paid | Balance at year end |
|---|---|---|---|
| 1 | $3,577 | $20,695 | $316,423 |
| 5 | $4,636 | $19,636 | $299,555 |
| 10 | $6,410 | $17,861 | $271,283 |
| 15 | $8,864 | $15,407 | $232,189 |
| 20 | $12,257 | $12,014 | $178,128 |
| 25 | $16,950 | $7,322 | $103,372 |
| 30 | $23,436 | $833 | $0 |
Principal finally overtakes interest in year 20. If you sell or refinance in the first decade, you’ll have paid down less of the loan than you might expect.
What extra payments do
Extra payments go straight to principal, so every dollar stops accruing interest for the rest of the loan. On the same $320,000 loan at 6.5%:
| Extra payment | Interest saved | Paid off sooner by |
|---|---|---|
| $200 every month | $105,428 | 6 years 7 months |
| $2,000 once a year | $88,832 | 5 years 7 months |
| $10,000 once, with payment 12 | $50,537 | 2 years 5 months |
Your required payment doesn’t change; the loan simply ends sooner. Before prepaying, check that your loan has no prepayment penalty. The CFPB notes these usually apply only when you pay off the whole loan within the first few years, not to small extra principal payments, but it’s worth confirming with your lender. Also make sure extra money is applied to principal, not held for next month’s payment.
How rate and term change the cost
Same $320,000 loan, different rates and terms:
| Rate and term | Monthly payment | Total interest | Total paid |
|---|---|---|---|
| 5.5%, 30 years | $1,816.92 | $334,095 | $654,095 |
| 6.5%, 30 years | $2,022.62 | $408,141 | $728,141 |
| 7.5%, 30 years | $2,237.49 | $485,491 | $805,491 |
| 6.5%, 20 years | $2,385.83 | $252,601 | $572,601 |
| 6.5%, 15 years | $2,787.54 | $181,758 | $501,758 |
Cutting the term from 30 to 15 years raises the payment by about $765 but saves over $226,000 of interest at the same rate, and 15-year loans usually carry lower rates too. A 30-year loan with disciplined extra payments sits in between and keeps the lower required payment as a safety net. If you already have a loan, our refinance calculator shows whether a new rate or term pays off after closing costs.
Tips for reading your schedule
- Your payment here is principal and interest only. Most mortgage payments also include property tax, homeowners insurance and sometimes PMI or HOA dues. Use the mortgage calculator for the full monthly cost.
- Use it to plan a payoff date. Try extra amounts until the payoff date hits a goal, such as retirement or a child’s college years.
- Compare with investing. Prepaying a 6.5% loan is a guaranteed 6.5% return. Whether that beats investing depends on your expected returns, taxes and need for cash on hand.
- Check before borrowing more. If you’re weighing a second loan against your home, the home equity loan calculator uses the same amortization math.
Assumptions and limitations
The calculator assumes a fixed rate, monthly payments made on time, interest charged monthly at one-twelfth of the annual rate, and amounts rounded to the cent. Adjustable-rate loans, interest-only periods, biweekly plans and daily-interest loans will differ somewhat. Extra yearly payments are applied with every 12th payment.
Sources
- Consumer Financial Protection Bureau: What is a prepayment penalty?
This calculator is for general information only and isn’t financial advice. Your lender’s schedule is the official record of your loan.
Frequently asked questions
What is an amortization schedule?
It's a table that lists every payment on a loan, split into the part that pays interest and the part that reduces your balance. The payment stays the same each month, but the interest share shrinks and the principal share grows as the balance falls. The last line shows the balance reaching zero.
Why do my early mortgage payments go mostly to interest?
Interest each month is charged on the balance you still owe, which is highest at the start. On a $320,000 loan at 6.5%, the first payment of $2,022.62 includes $1,733.33 of interest and only $289.29 of principal. As the balance drops, less interest is due and more of the same payment goes to principal.
How much can extra payments save?
Quite a lot, because every extra dollar skips all the future interest it would have accrued. On a $320,000, 30-year loan at 6.5%, an extra $200 a month saves about $105,428 in interest and ends the loan 6 years 7 months early. The earlier you start, the bigger the effect.
Is it better to pay extra monthly or once a year?
Spread over a year the amounts are similar, but paying monthly gets money to work a little sooner. In our example, $200 extra each month saves about $105,428, while a single $2,000 payment each year saves about $88,832. Both are far better than nothing; pick the schedule you can stick to.
Does this work for car loans and personal loans?
Yes. Any fixed-rate loan with equal monthly payments amortizes the same way, whether it's a mortgage, auto loan, student loan or personal loan. Enter the amount, rate and term in years. For a mortgage payment that includes property tax, insurance and PMI, use the mortgage calculator instead.
Can I download the amortization schedule?
Yes. Use the Download CSV button under the schedule to open it in Excel, Numbers or Google Sheets. It includes every payment with its date, principal, interest, any extra payment and the remaining balance.
Updated November 2026. Results are estimates for educational purposes and depend on the inputs you provide.