Loan Calculator
Loan calculator for any amount, rate and term. See your monthly payment, total interest and total cost instantly, with the amortization math shown.
Formula
M = P · r / (1 − (1 + r)^−n), where r is the monthly rate and n the number of months.
Use it from the API
curl "https://moltcalc.com/api/calc/loan?amount=20000&rate=7&years=5"
See the API docs for every endpoint and the input schema.
FAQ
How is a monthly loan payment calculated?+
The calculator uses the standard amortization formula M = P × r / (1 − (1 + r)^−n), where P is the loan amount, r is the monthly interest rate (annual rate divided by 12), and n is the number of monthly payments. Every payment is the same size, but early payments are mostly interest and later ones mostly principal.
Does a longer loan term lower my payment?+
Yes, spreading the same loan over more months lowers each monthly payment, but you pay interest for longer, so the total interest cost goes up. Compare the total of payments, not just the monthly figure.
How do I figure out total interest on a loan?+
Multiply the monthly payment by the number of payments, then subtract the amount you borrowed. The calculator shows this as the total interest line.