Debt Payoff Calculator
Find out exactly when a debt will be gone, and how much of your money is actually going toward interest instead of the balance itself. Works for credit cards, personal loans, or any debt charging interest on what’s left owing.
Why your balance doesn’t shrink as fast as you’d expect
Picture your debt like a bathtub that’s draining, but someone keeps a tap running into it at the same time. Your monthly payment is the drain — but interest is that tap, constantly adding a bit more back in based on however much is still in the tub. Early on, when the balance is high, more of your payment gets eaten by that “tap” (interest), and less actually drains the tub (reduces your balance). That’s why the first few payments on a debt can feel like they barely move the number.
M = monthly payment · P = balance owed · r = monthly interest rate (annual rate ÷ 12)n = number of monthly payments
The fastest lever you actually control: extra payments
You usually can’t negotiate your interest rate down easily, but you can control how much you pay each month — and that lever matters more than most people realize. Because interest is calculated on whatever balance remains, every extra dollar you throw at the debt today stops future interest from ever being charged on it. This is why even a small, consistent increase in your monthly payment can shave months off your payoff time and meaningfully cut the total interest paid.
- Paying only the minimum is the slowest, most expensive path. Minimum payments are often calculated to just barely cover interest plus a sliver of principal — which is exactly why they can stretch a debt out for years.
- Extra payments go straight to principal. Most lenders apply any amount above your required payment directly to the balance, which is where it does the most good.
- If you have multiple debts, the order you pay them off in changes your total cost — see our Snowball vs. Avalanche comparison tool for that side of the decision.
Frequently asked questions
Because interest is calculated on your full remaining balance, and that balance is at its highest right at the start. As the balance drops, less of each payment goes to interest and more goes to knocking down the principal — progress accelerates the longer you stick with it.
The balance actually grows instead of shrinking — this calculator will warn you if that’s the case. It means your payment needs to increase before any real progress can be made.
A one-time extra payment permanently reduces your balance, which reduces all future interest charges on it — even if you go back to your normal payment the next month, you’ll still finish earlier than originally planned.
A common rule of thumb: if your debt’s interest rate is higher than what you could reasonably expect to earn investing (often compared to the ~7–10% long-term stock market average), paying off the debt first usually wins, since it’s a guaranteed “return” equal to the interest rate you stop paying.
Have more than one debt to juggle?
See which payoff order saves you the most money.
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