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Loan calculator

Estimate monthly payments, total interest and total repayment.

Monthly payment
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Guide

Loan payment formula

This calculator uses the standard amortized loan formula. It assumes a fixed interest rate and equal monthly payments for the full term. It is useful for quick estimates before comparing real offers.

Four repayment methods: equal payment keeps every payment the same; equal principal repays a fixed share of the principal each month so the payment falls over time; graduated does the opposite, starting low and rising each month; interest-only pays just the interest monthly and the whole principal at the end.

Tip: enter the annual interest rate — the calculator converts it to a monthly rate for you. A longer term lowers each monthly payment but raises the total interest, so compare the total cost, not just the monthly amount.

📖 Related guide: Loan repayment methods: equal payment vs equal principal

Formulas used

Equal payment: A = P · r(1+r)ⁿ ÷ ((1+r)ⁿ − 1) (r = monthly rate, n = months)
Equal principal: each month you repay P ÷ n, plus interest on the remaining balance
Total interest: (monthly payment × number of payments) − principal

How this calculator works

CalcBloom builds the schedule month by month in your browser: it applies your rate to the remaining balance, subtracts the principal portion, and repeats until the loan is repaid. It is an estimate — real offers add fees, insurance, APR rounding and lender-specific rules. Nothing you enter is sent to a server.

Last reviewed: 2026-07

FAQ

Frequently asked questions

Does this include fees or taxes?

No. It estimates principal and interest only.

Can I use a zero interest rate?

Yes. With 0% interest, the payment is simply amount divided by months.

Is this financial advice?

No. It is an estimate, not financial advice.

Why does a longer term cost more in total?

You borrow the money for more months, so interest builds up for longer. The monthly payment is smaller, but the total interest you pay is usually higher.

What is the difference between APR and the interest rate?

The interest rate is the cost of borrowing the principal. APR also includes some fees, so it is usually a little higher and is better for comparing offers. This calculator uses a plain interest rate.

Does this include fees or insurance?

No. It estimates principal and interest only. Real loan offers can add origination fees, insurance, taxes and APR rounding that vary by lender, so treat the result as a planning figure.

What is the difference between equal payment and equal principal?

Equal payment keeps every monthly payment the same, so early payments are mostly interest. Equal principal repays the same principal each month, so payments start higher and fall over time, with less total interest.