Debt Payoff Calculator
Calculate how long it will take to pay off your debt and how much interest you'll pay.
The Formula
Principal Paid = Payment − Interest
Months to payoff = −log(1 − r×P/M) / log(1+r)
r = 0.015 · M = $250
Months = −log(1 − 0.015×8000/250) / log(1.015)
= 47 months · $3,724 interest
How Long Will It Take to Pay Off Your Debt?
Enter your current balance, interest rate, and monthly payment to see exactly when you will be debt-free and how much you will pay in total interest. This is often a sobering exercise. A $10,000 personal loan at 18% APR paid off at $250 per month takes over 5 years and costs nearly $5,000 in interest alone. Seeing that number can be the motivation needed to find an extra $100 or $200 a month to accelerate the payoff. Our calculator also shows you how much each extra dollar saves.
The Avalanche Method: Pay Less Interest Overall
If you have multiple debts, the avalanche method directs extra payments toward the highest-interest debt first while making minimum payments on everything else. Once the highest-rate debt is eliminated, you roll that freed-up payment to the next highest. This minimizes total interest paid over time and is mathematically the most efficient approach. It works best for people who stay motivated by the numbers and can be patient when early progress feels slow on a large high-rate debt.
The Snowball Method: Stay Motivated
The snowball method ignores interest rates and attacks the smallest balance first. Pay minimums on everything else and throw every extra dollar at the smallest debt until it is gone, then move to the next smallest. It typically costs a bit more in total interest than the avalanche approach, but research consistently shows that getting those quick wins — eliminating entire accounts — keeps people engaged and on track. The best debt payoff strategy is the one you will actually stick with.
Frequently Asked Questions
What is the debt avalanche method?
The avalanche method focuses all extra payments on the debt with the highest interest rate, while paying minimums on everything else. Once that debt is paid off, you roll the freed-up payment to the next highest-rate debt. This approach minimizes total interest paid and is the most cost-efficient strategy mathematically.
What is the debt snowball method?
The snowball method targets the smallest balance first, regardless of interest rate. Once that debt is eliminated, you roll its payment to the next smallest balance. It tends to cost more in interest than the avalanche approach, but the quick wins of eliminating accounts can provide powerful motivation for people dealing with multiple debts.
Should I pay off debt or invest?
It depends on the interest rate. High-interest debt above 7–8% should generally be paid off before investing, because the guaranteed return of eliminating that interest beats uncertain market returns. For low-interest debt under 4–5% — like many student loans or mortgages — the calculus is closer, especially if you have an employer 401(k) match available. Most advisors recommend capturing the full employer match first, then aggressively paying high-interest debt.
What is debt consolidation and does it help?
Debt consolidation rolls multiple debts into a single loan — ideally at a lower interest rate. It simplifies payments and can save money if the new rate is meaningfully lower. The risk: some people run up new balances on the cleared cards after consolidating. Consolidation only helps long-term if you also address the spending habits that created the debt in the first place.
How much extra per month makes a real difference?
Even small extra payments matter. On a $10,000 loan at 15% APR with a $250 minimum payment, adding just $100 per month cuts about two years off the payoff and saves over $2,000 in interest. Use this calculator to model different payment amounts and find the number that works for your budget.