Monthly Payment Calculator with Interest – Free & Client-Side

A versatile installment calculator for any loan, mortgage, or promissory note. Compare fully amortizing principal-and-interest installments against interest-only repayment structures.

Mathematical Formula

Amortizing: P × [r(1+r)^n] / [(1+r)^n - 1]; Interest-Only: P × r.

Frequently Asked Questions

What is the risk of an interest-only loan?
With an interest-only loan, your monthly payments only cover interest charges, meaning your principal balance never decreases. When the interest-only period ends, payments will jump substantially to begin paying off principal.
How does loan term length affect monthly payments versus total interest?
A longer loan term lowers your required monthly installment by spreading principal over more months, but significantly increases total cumulative interest paid over the life of the loan.

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