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Loan & Mortgage Calculator

Calculate your monthly payments and see the full amortization schedule

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About Loan Calculator

Enter the amount, the annual interest rate and the term, and this calculator returns the fixed monthly payment for an amortising loan — a mortgage, a car loan or a personal loan — along with the full repayment schedule and the total interest you will pay.

The formula behind the payment

A fixed-rate loan uses the standard amortisation formula M = P · i(1+i)ⁿ / ((1+i)ⁿ − 1), where P is the amount borrowed, i is the monthly rate — the annual rate divided by twelve — and n is the total number of payments. The payment stays constant, but its composition does not: early payments are mostly interest, and the balance shifts towards principal as the loan matures.

Worked example: 300,000 over 20 years at 12% annual. The monthly rate is 12% ÷ 12 = 1%, and n = 240 payments. The formula gives a payment of about 3,303 — so about 792,800 is repaid in total, of which roughly 492,800 is interest. The interest exceeds the amount borrowed, which is the part most people do not expect.

Why is so little of my early payment going to principal?

Because interest is charged on the balance still outstanding, and at the start that balance is nearly the whole loan. In the example above the first payment puts about 3,000 towards interest and only about 303 towards principal. The ratio inverts gradually — which is why an extra payment made in year one removes far more total interest than the same amount paid in year fifteen.

What does the calculator not include?

Only principal and interest. Real loan offers add arrangement fees, compulsory insurance, taxes and sometimes an early-repayment charge, all of which raise the true cost. Compare offers on their published APR rather than the headline rate, and treat the figure here as the baseline the extras are added to.

Try our other free tools: percentage calculator, compound interest calculator, and unit converter.