Loan Calculator
Estimate a fixed-rate loan’s monthly payment, total interest and repayment schedule. Add a regular extra payment to see how it changes the payoff time.
Loan Calculator
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Guide updated 6 October 2026
How to use the monthly loan payment calculator
Enter the amount borrowed, the annual contract interest rate and the number of monthly payments. Use months, so a three-year term is 36. Add an optional amount paid toward principal every month, then calculate. The result separates the scheduled payment from the effect of the extra payment.
Use the downloadable repayment CSV when you want to compare offers in a spreadsheet. It lists payment number, payment, interest, principal repaid and remaining balance. The calculation supports up to 600 months and a rate of zero.
Fixed-rate payment formula and a zero-interest loan
For principal P, monthly rate r and n payments, payment = P × r ÷ [1 − (1 + r)−n]. The monthly rate is the annual percentage divided by 1,200. This is a reducing-balance model with equal monthly periods and payments at each period’s end.
At 0% interest, payment = P ÷ n. A fictional 12,000 loan over 24 months therefore costs 500 per month before fees. At nonzero interest, each payment includes interest on the remaining balance and a principal portion.
Loan amount, term and total cost: what to compare
Compare loans using the same amount, term and fee treatment. A longer term can make the monthly amount smaller while increasing total interest. A lower payment by itself does not establish that an offer costs less.
For a 10,000 loan at 6% over 36 months, the estimate is 304.22 per month, with about 951.90 total interest. The example is illustrative and is not an available lending offer. Enter the actual rate from your lender.
How regular extra payments change the schedule
An extra monthly payment reduces principal earlier, so less interest accrues in later months. The calculator keeps the original scheduled payment, applies the entered extra amount each month, and shortens the schedule when the balance is cleared. The last payment is reduced to the amount needed.
The extra payment is assumed to go directly toward principal without a fee. Check whether your lender allows that treatment and whether it imposes early repayment charges. This version does not schedule one-off or annual extra payments.
Interest rate versus APR and excluded charges
Use the nominal contract interest rate in the form. APR can include mandatory fees as well as interest, so it may differ from the rate used to calculate a payment. Putting APR into this simple model can give an approximate comparison, but it does not reproduce a disclosure or calculate APR.
The result excludes origination fees, insurance, late charges, property taxes and variable-rate changes. Add financed costs to principal only when the contract actually finances them. Keep upfront costs separate when comparing the full cash cost.
Common loan calculator issues
If the result differs from a statement, check monthly versus annual rates, the number of payments and whether the lender uses daily interest. Payment dates, odd first periods, rounding rules and extra-payment timing can all affect a lender’s figures.
The CSV rounds amounts for display, while the calculation carries more precision internally. This tool is for level-payment amortizing loans; it does not model balloon payments, interest-only loans or credit cards.
Loan calculator FAQs
Can I use any currency? Yes, all monetary inputs and outputs use the same currency units; this is not a currency converter. Does the estimate include fees? No, unless you include a financed fee in the principal yourself.
Will it tell me whether I qualify? No. Approval, affordability and quoted rates depend on the lender. Can I use it for a mortgage? It estimates principal and interest only; escrow, tax and insurance are outside the calculation.