Loan Repayment Calculator

Given your balance and rate, pick either a target payoff term OR a monthly payment you can afford — we solve for the other and show the full repayment picture.

How it works

Both modes come from the same amortization identity. To solve for payment given term we use PMT = P·r·(1+r)ⁿ / ((1+r)ⁿ − 1). To solve for term given payment we invert to n = −ln(1 − P·r/PMT) / ln(1 + r) and round up so the last payment is a stub.

Frequently asked questions

What if my payment is too low?

If your monthly payment is less than the monthly interest (balance × rate ÷ 12), the balance grows instead of shrinking. This is called negative amortization. Raise the payment above that threshold.

How do I pick a good term?

Pick the shortest term where the monthly payment is comfortably below 15–20% of your take-home pay. Shorter terms save enormous interest.

Does this work for any loan?

Yes — any fixed-rate, fully-amortizing loan: personal, auto, student, mortgage. Not credit cards where the minimum floats.

How is 'months to payoff' derived?

From the closed-form formula n = −ln(1 − Pr/PMT) / ln(1 + r). It gives the exact number of payments needed; we round up to a whole month.

Can I add extra payments?

Use our Extra Payment or Early Payoff calculators. This one focuses on the level-payment case for the base plan.

Related calculators