Loan Calculator

FINANCIAL MATH

Find the monthly payment, total cost, and total interest on a fixed-rate loan. Enter the amount, rate, and term.

Monthly Payment
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Principal and interest.

Usage Tip

Compare the total interest, not just the monthly payment — a lower payment over a longer term often costs much more overall.

THE MATH
M = P × i(1+i)^N ÷ ((1+i)^N − 1)
i = monthly rate (annual ÷ 12), N = number of months
A fixed-rate loan is repaid in equal monthly payments; early payments are mostly interest, later ones mostly principal.
Shortening the term raises the payment but cuts total interest sharply.
This assumes a fixed rate and equal monthly payments (an amortizing loan).
Extra payments go straight to principal and save interest, shortening the loan.
Fees and insurance are not included; the real APR may be higher than the rate.
Practical Notes

For a fixed rate loan, the monthly payment stays the same for the whole term. It is calculated so that the balance reaches zero after the last payment, with each payment covering the interest owed for that month and reducing the principal by the rest. Early payments are mostly interest, and later payments are mostly principal.

The total interest is the sum of all payments minus the original amount borrowed. A longer term lowers the monthly payment but increases the total interest, and a higher rate raises both. Extra payments toward principal shorten the loan and cut interest. This calculator does not include fees or insurance, so check the lender’s full costs before borrowing.

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The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.