Why does a slightly bigger payment save so many months?

Because the extra goes entirely to principal, and every dollar of principal killed stops compounding against you. On a high-APR balance, moving from $300 to $400 a month often cuts the timeline nearly in half.

Avalanche or snowball?

Avalanche (highest APR first) is mathematically optimal; snowball (smallest balance first) wins if visible progress keeps you paying. The best method is the one you will not abandon in month four.

Should I pay off debt or save for taxes first?

Tax money is not yours: set aside for quarterly taxes before extra debt payments, because the IRS charges penalties on top of interest. After that, a 24% APR balance beats almost any investment return you will find.

Personal finance

Debt payoff calculator

A balance, a rate, a monthly payment: three numbers decide how many months you are carrying the debt and what the ride costs. This amortizes it month by month, including the ugly case where the payment barely dents it.

Your numbers

Currency

Current balance

What you owe today.

APR

The annual rate on the statement. Credit cards commonly 20-28%.

Monthly payment

What you will actually pay each month, fixed.

Results

Months to zero26months2 years and 2 months

First month's interest: $200
Total interest paid: $2,899
Total paid: $12,899

Estimate

Worked example: 10,000 at 20% APR, paying 300 vs 500

workingfigures.com/calculators/debt-payoff-calculator

The formula

Each month: interest = balance × APR ÷ 12; the rest of your payment reduces the balance. If the payment does not exceed the first month's interest, the balance never falls.

What this ignores

Fees, penalty-rate changes, new charges on the card, and minimum-payment schedules that shrink as the balance falls (which stretch payoff far longer than a fixed payment). Fixed payment, fixed rate, no new spending.

FAQ

Why does a slightly bigger payment save so many months?: Because the extra goes entirely to principal, and every dollar of principal killed stops compounding against you. On a high-APR balance, moving from $300 to $400 a month often cuts the timeline nearly in half.
Avalanche or snowball?: Avalanche (highest APR first) is mathematically optimal; snowball (smallest balance first) wins if visible progress keeps you paying. The best method is the one you will not abandon in month four.
Should I pay off debt or save for taxes first?: Tax money is not yours: set aside for quarterly taxes before extra debt payments, because the IRS charges penalties on top of interest. After that, a 24% APR balance beats almost any investment return you will find.