DebtMastery

Debt Payoff Calculator

The most accurate way to see your debt-free date. Uses the same compound interest math your lender uses — so you know exactly where every dollar goes.

How this works: Enter your real debt numbers. The calculator uses compound interest math to show your exact payoff date and how much interest you'll pay. No email required — your data never leaves your browser.

Your Debt

Enter your current balance, interest rate, and what you can pay each month.

$
22.99%
0% (no interest)36% (predatory)
$

$163/mo goes to interest · $87/mo reduces principal

Your Payoff Plan

Results update live as you adjust the inputs.

Your Debt-Free Date
December 2030
4 yr 8 mo from today
Total Paid
$13,883
Principal + interest
Total Interest
$5,383
63% of balance
Payoff Time
4 yr 8 mo
at current rate
💡 Pro tip: Adding just $50 extra per month (20% more) would shave approximately 14 months off your timeline and save hundreds in interest.
The interest treadmill, explained: With a 22.99% APR on $8,500, you pay $162.85 in interest on the very first month alone — before a single dollar reduces your principal. This is why paying more than the minimum is so powerful.

How the Debt Avalanche Method Works

The Debt Avalanche strategy directs every extra dollar toward the debt with the highest Annual Percentage Rate (APR), while paying the minimum on all others. Once the highest-APR debt is eliminated, its freed-up payment rolls entirely to the next highest — creating an accelerating "avalanche" of debt destruction.

Why it saves money: Interest compounds daily on most credit cards and loans. By eliminating the most expensive debt first, you reduce the total interest accruing across your portfolio every single month. Studies show the Avalanche method saves the average household hundreds to thousands of dollars in total interest.

How the Debt Snowball Method Works

The Debt Snowball strategy targets the smallest balance first, regardless of interest rate. Each eliminated debt frees up its minimum payment, which adds to the next target — the "snowball" growing as it rolls downhill.

Why it works behaviorally: Research from Harvard Business Review found that people who paid off their smallest balances first were more likely to stay motivated and eliminate all their debt. The psychological win of a zero balance is real — and for many people, staying consistent matters more than mathematical optimization.

The Math Behind the Calculator

This calculator uses standard amortization formulas to compute your payoff timeline:

  • Monthly interest: Balance × (APR ÷ 12 ÷ 100)
  • Principal reduction: Monthly payment − Monthly interest
  • Payoff months: −ln(1 − r·P/M) ÷ ln(1 + r)

All calculations run client-side in your browser. No financial data is ever transmitted or stored.