Loan Payoff Calculator

A loan payoff calculator answers a different question than a typical loan calculator: instead of telling you the monthly payment for a given term, it tells you how long a chosen monthly payment will take to clear your balance. This is especially useful when you're paying extra principal each month and want to see exactly how much sooner the debt disappears.

The math iterates month by month — each payment first covers the interest accrued, and whatever is left chips away at the principal. The bigger the payment relative to the interest charge, the faster the balance falls. Even a modest extra principal payment can shave years off a long-term loan because every dollar of extra principal also eliminates all the future interest that dollar would have generated.

Suppose you have a $20,000 balance at 7% APR and you pay $500/month:

• Monthly interest rate: 7% ÷ 12 = 0.005833
• Month 1 interest: $20,000 × 0.005833 = $116.67
• Month 1 principal reduction: $500 − $116.67 = $383.33
• Time to payoff: roughly 4 years
• Total interest: about $2,991

Bump the payment to $700/month and the same loan disappears in about 2 years 8 months with around $1,919 in total interest — over $1,000 in savings, plus you're debt-free 16 months sooner.

• Planning extra principal payments — see how an extra $50, $100, or $200/month accelerates payoff.
• Choosing between debt-payoff strategies — model avalanche (highest rate first) vs snowball (smallest balance first) on each balance.
• Setting a debt-free target date — work backward from a goal date to find the required monthly payment.
• Comparing windfalls — see how a $5,000 tax refund applied to principal changes the timeline.
• Evaluating biweekly schedules — quantify how an extra full payment per year shortens the loan.

• Paying just under the minimum. If your payment doesn't cover the monthly interest, the balance grows and the loan never pays off.
• Not specifying "principal only" for extra payments. Many servicers apply extras to next month's payment instead of principal, gaining you nothing.
• Tapping retirement accounts to pay off low-rate debt. A 4% mortgage isn't worth a 10% early-withdrawal penalty plus income tax on a 401(k) draw.
• Ignoring prepayment penalties. A few subprime auto loans and older mortgages charge 1–3% of the prepaid balance.
• Sacrificing emergency savings to pay off debt faster. Without a 1–3 month buffer, the next surprise expense pushes you back into new debt.