Work out the monthly payment, the total interest, and the full amortization schedule for any fixed-rate loan.
This calculator uses the standard equal-instalment (amortizing) formula. It does not include origination fees, insurance, late charges or any lender-specific add-ons, and it assumes a fixed rate for the whole term. Lenders may round differently — treat the result as an estimate.
On an amortizing loan the interest is charged on the balance that is still outstanding, so the earliest payments are almost entirely interest and the last ones are almost entirely principal. That is why a loan at 7.5% over five years costs noticeably more than 7.5% of what you borrowed — the rate is applied to the balance every month, not once. It also explains why extra payments are so effective: a dollar paid early removes every future month of interest that dollar would have generated.
Early payments are mostly interest. The crossover — where principal finally overtakes interest — is the point most borrowers never see.
$25,000 borrowed at 7.5% over 5 years — a typical used-car or personal loan.
Monthly payment, total interest and a full amortization schedule for any fixed-rate loan. Add extra monthly payments to see the months and dollars of interest they save. CSV export.
An amortizing loan uses a fixed monthly payment calculated as P × r / (1 − (1 + r)^−n), where P is the principal, r is the monthly interest rate (the annual rate divided by twelve) and n is the number of monthly payments. The payment stays constant for the whole term, but what it is made of changes every month: interest is charged on the balance still outstanding, so early payments are mostly interest and late payments are almost entirely principal.
A 7.5% loan over five years does not cost 7.5% of the amount borrowed — it costs considerably more, because the rate is applied to the outstanding balance every month rather than once. On a $25,000 five-year loan at 7.5%, the interest total comes to roughly $5,000, or about 20% of the principal. Stretch the same loan to ten years and the monthly payment falls, but the interest total roughly doubles. Long terms buy affordability with interest.
Any extra amount you pay goes entirely to principal, which removes every future month of interest that principal would have generated. That compounding effect is why relatively small extra payments have an outsized result: adding $200 a month to a 30-year, $200,000 loan at 6% pays it off several years early and saves tens of thousands in interest. This calculator models the extra payment and reports both the months saved and the interest saved.
The schedule shows, for each year of the loan, how much of your payments went to principal, how much went to interest, and what balance remained at the end. The balance falls slowly at first and steeply later — the mirror image of the principal-versus-interest split. Reading the schedule is the fastest way to see why refinancing early in a loan saves far more than refinancing late, and why paying extra in the first years is worth more than the same amount paid near the end.
The result covers principal and interest only. It excludes origination fees, application fees, insurance products sold with the loan, late charges, and any prepayment penalties. It also assumes a fixed rate for the entire term, so it does not model variable-rate loans whose payment changes with an index. Lenders may round the payment to the nearest cent differently, which shifts the final instalment by a small amount.
This tool handles any fixed-rate instalment loan — personal, business, or auto — with principal, rate and term as the only inputs. The mortgage calculator adds home-specific fields such as down payment, property tax, homeowners insurance and PMI, which is why the two are kept separate.
Yes, and the saving is largest early in the loan. Extra payments reduce principal, and principal is what interest is charged on, so every dollar paid early eliminates all the future interest that dollar would have accrued. The calculator reports both the months and the dollars saved.
Lenders may use a different day-count convention, round the payment differently, or include fees and insurance in the amount financed. A difference of a few cents to a few dollars is normal. If the difference is larger, check whether your quoted rate is the nominal rate or the APR.
It is cheaper per month and more expensive overall. A longer term lowers the monthly payment but increases the total interest, sometimes substantially. The right answer depends on whether you need the cash-flow relief or can afford to pay the loan down faster.
Yes. The Export CSV button generates the full year-by-year schedule — principal, interest and remaining balance for each year — so you can open it in a spreadsheet or keep it with your loan documents.
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