How to use the payment calculator
Choose what you know. With Fixed term, enter the loan amount, the number of years and the interest rate to get the monthly payment. With Fixed payments, enter the amount you plan to pay each month instead, and the calculator shows how long it takes to clear the debt. Both give the total interest, a principal and interest chart and a month-by-month schedule you can export.
Payment formulas
For a fixed term the monthly payment is M = P × r ÷ (1 − (1 + r)−n), where P is the loan amount, r the yearly rate ÷ 12 and n the number of months. For a fixed payment the number of months is n = −ln(1 − P × r ÷ M) ÷ ln(1 + r). The result is usually not a whole number: the last payment is a part of a regular one.
Payment calculator example
A loan of $200,000.00 at 6% over 15 years costs $1,687.71 a month, $303,788.46 in total, of which $103,788.46 is interest. Paying $2,000.00 a month instead clears it in 11 years 6.98 months, with $77,951.44 of interest: $25,837 less than with the 15-year payment.
Monthly payment by loan term
| Term | Monthly payment | Total paid | Total interest |
|---|---|---|---|
| 5 years | $3,866.56 | $231,993.62 | $31,993.62 |
| 10 years | $2,220.41 | $266,449.20 | $66,449.20 |
| 15 years | $1,687.71 | $303,788.46 | $103,788.46 |
| 20 years | $1,432.86 | $343,886.91 | $143,886.91 |
| 25 years | $1,288.60 | $386,580.84 | $186,580.84 |
| 30 years | $1,199.10 | $431,676.38 | $231,676.38 |
For $200,000.00 at 6%. The 30-year payment is $1,199.10, but its interest, $231,676.38, is more than 7 times the interest of the 5-year loan.
Payoff time by monthly payment
| Monthly payment | Time to pay off | Total interest |
|---|---|---|
| $1,500 | 18 years 4.27 months | $130,406.96 |
| $2,000 | 11 years 6.98 months | $77,951.44 |
| $2,500 | 8 years 6.42 months | $56,050.81 |
| $3,000 | 6 years 9.30 months | $43,886.76 |
| $4,000 | 4 years 9.68 months | $30,720.54 |
The payment has to be more than the first month's interest, $1,000.00 here, or the balance never goes down. Every dollar above it goes to the principal, so the first few hundred dollars over that line shorten the loan the most.
Payment formulas in Excel
- Monthly payment:
=PMT(6%/12,180,-200000)returns $1,687.71. - Months to pay off:
=NPER(6%/12,-2000,200000)returns about 138.98. - Total interest of the fixed term:
=PMT(6%/12,180,-200000)*180-200000returns $103,788.46.
Tips to lower the cost
- A shorter term or a larger payment means less interest overall.
- Even a small extra amount each month shortens a long loan by years.
- Compare offers by their APR, which includes the fees.
Related calculators
To add extra monthly, yearly or one-time payments to a schedule, use the amortization calculator. The loan calculator handles biweekly or weekly payments, other compounding and deferred loans, the mortgage calculator adds property tax, insurance and PMI, and the credit card calculator works out the payoff of a card balance.