Loan Calculator
Calculate the monthly payment, total interest, and payoff for any fixed-rate loan.
A worked example
Running this tool on current national benchmarks (Federal Reserve / Freddie Mac via FRED (St. Louis Fed)) — swap in your own numbers to see how the result moves.
- Solve for
- Monthly payment
- Loan amount
- $25,000
- Interest rate (APR)
- 11.57%
- Loan term
- 5 years
- Extra monthly payment
- $0
$25,000 at 11.57% over 5 years
- Loan amount$25,000
- Monthly payment$550.69
- Total interest$8,042
How the monthly payment changes with loan amount
Holding the other inputs at the example above, here is how the result moves as loan amount changes.
| Loan amount | Monthly payment | Loan amount |
|---|---|---|
| $12,500 | $275.35 | $12,500 |
| $25,000 | $550.69 | $25,000 |
| $37,500 | $826.04 | $37,500 |
| $50,000 | $1,101.39 | $50,000 |
The math behind it
A general fixed-rate loan calculator. The monthly payment is set so equal payments repay the full loan by the end of the term at your rate. Each month, interest is charged on the outstanding balance and the rest reduces principal, so early payments lean toward interest and later ones toward principal. You can solve for the payment from a loan amount, or for the amount a chosen payment supports, and add an optional extra monthly payment that goes straight to principal.
Assumptions & limits
- A fixed interest rate applies for the whole term, compounding monthly.
- Each payment covers that month's interest first, with the remainder reducing principal.
- Any extra monthly payment reduces principal directly, shortening the term and lowering total interest.
- The result is principal and interest only — no fees, insurance or taxes.
Common questions
What loans does this calculator cover?
Any fixed-rate loan that repays in equal monthly installments — personal loans, auto loans, student loans, small business loans and similar. Enter the amount, rate and term. For loans with special features like balloon payments, deferrals or origination fees, use the dedicated calculators that model those directly.
Does a lower rate or a shorter term save more?
Both cut interest, but in different ways. A lower rate reduces the interest on every dollar borrowed; a shorter term reduces how long you pay interest at all, usually at the cost of a higher monthly payment. Try different combinations here to see the trade-off between payment size and total interest.
How does adding an extra monthly payment help?
Extra payments go entirely to principal, so they remove that balance from all future interest. Even a small amount added each month shortens the term and cuts total interest. Enter an extra amount to see exactly how much it saves on your loan.