Debt Payoff Calculator

This debt payoff calculator models every credit card, personal loan, and student loan you enter, then projects the exact month you will be debt free based on your chosen strategy. It also doubles as a debt to income ratio calculator by showing you what your total minimum payments are relative to any income you want to test against, so you can plug the same numbers into a DTI calculator check.

1. Add every debt you carry. Use the + Add Debt button to create a row for each account. Enter the current balance, the APR from your most recent statement, and the minimum monthly payment the lender requires. Accuracy on APR matters most for credit cards, which often charge 18% to 29.99%.
2. Enter an extra monthly payment. This is anything above the combined minimums. Even $50 extra per month can shave years off a credit card balance. If you are unsure what you can afford, start with the default $200 and adjust.
3. Pick a payoff strategy. Avalanche sorts your debts by APR and attacks the highest rate first. Snowball sorts by balance and wipes out the smallest one first. The calculator shows both totals side by side so you can see the dollar cost of choosing motivation over math.
4. Compare against minimums. The lower panel simulates making only the required minimum each month. The gap between the two scenarios is what your extra payment is actually buying you in time and interest saved.

The debt-free date is the month your last dollar of balance is paid. Total interest is the sum of every interest charge along the way, which for a high-APR credit card can easily exceed the original balance if you only pay minimums. The interest-saved figure is the single most useful number on this page, because it tells you the real return on every extra dollar you put toward debt instead of spending it.

Three formulas do all the heavy lifting behind this debt calculator and the DTI check that lenders run when you apply for a mortgage or auto loan.

1. Months to Payoff (Amortization Inversion)

N = −log(1 − (r × B) ÷ P) ÷ log(1 + r)

Where:
  B = current balance
  r = APR ÷ 12 (monthly rate as a decimal)
  P = monthly payment
  N = number of months until payoff

Example: $5,000 balance at 24.99% APR, $150/month payment
  r = 0.2499 ÷ 12 = 0.020825
  N = −log(1 − (0.020825 × 5000) ÷ 150) ÷ log(1.020825)
    = −log(1 − 0.6942) ÷ log(1.020825)
    = −log(0.3058) ÷ 0.02062
    ≈ 58 months (4 years 10 months)

Total interest paid = (150 × 58) − 5000 = $3,700

If the monthly payment is smaller than the monthly interest charge (P ≤ r × B), the log becomes undefined because the balance never shrinks. That is the math behind "minimum payment trap" warnings on credit card statements.

2. Debt-to-Income Ratio (DTI)

DTI = Total Monthly Debt Payments ÷ Gross Monthly Income × 100

Example: $5,500 gross monthly income
  Mortgage payment:       $1,450
  Auto loan:                $385
  Student loans:            $220
  Credit card minimums:     $145
  ────────────────────────────────
  Total monthly debt:     $2,200

  DTI = 2200 ÷ 5500 × 100 = 40%

This is the exact formula lenders use when you apply for a mortgage. Gross income means before taxes. Only required monthly debt payments count, not utilities, groceries, insurance, or subscriptions. If you want to calculate debt to income ratio quickly, add the minimum payment column in this calculator and divide by your monthly gross.

3. Avalanche vs Snowball Ordering

Avalanche order:  sort debts by APR, descending
Snowball order:   sort debts by balance, ascending

Each month:
  1. Apply minimum payment to every debt
  2. Apply extra payment to the first debt in sorted order
  3. When a debt hits zero, roll its minimum + extra
     into the next debt in the sorted list

Avalanche is provably optimal for total interest paid, because interest compounds fastest on the highest-rate account. Snowball trades a few hundred dollars of extra interest for the psychological win of closing an account sooner, which studies from Northwestern and the Journal of Consumer Research show dramatically improves completion rates.

Quick Reference: $20,000 Debt at 18% APR

How long it takes to clear a $20,000 credit card balance at 18% APR depends almost entirely on how much above the interest charge you can pay each month.

Raising the payment from $400 to $600 (50% more each month) cuts both the payoff time and the interest paid by more than half, because every extra dollar attacks principal instead of feeding the interest charge.

A debt payoff calculator only projects what happens if you stick to the plan. The harder questions are which plan to choose, what DTI ratio lenders will accept, and how to cut your APR so the math tilts in your favor.

Avalanche vs Snowball: A Concrete 3-Debt Scenario

Consider three debts and $500/month of extra payment on top of minimums:

Avalanche order attacks Card A first (highest APR), then Card B, then the personal loan. Snowball order clears Card B first ($1,200, the smallest), then the personal loan, then Card A. Simulating both over roughly 32 months, avalanche saves about $820 in total interest. Snowball gets you to your first "debt paid off" celebration in month 3 versus month 18 for avalanche. If you have quit debt payoff plans in the past, that first-closure milestone is worth the $820. If you have successfully stuck with long financial goals before, take the avalanche money.

DTI Thresholds Lenders Actually Use

Your debt to income ratio is the single most important number on a mortgage application after your credit score. Every debt calculator, including this one, feeds into the same DTI formula lenders run. Standard thresholds:

The 43% line is the legal ceiling for a "Qualified Mortgage" under CFPB rules, which is why most banks treat it as a hard cutoff. If your DTI is borderline, paying off even one small balance (for example, a $1,500 credit card with a $45 minimum) can drop your DTI by a full percentage point and move you into the next bracket.

How to Cut Your APR Before You Pay It Down

A lower APR reduces how much of each payment is eaten by interest, so the same monthly dollars clear the balance faster. Three options, ordered roughly by effectiveness:

1. 0% balance transfer cards. Chase, Citi, and Wells Fargo regularly offer 15 to 21 months at 0% on balance transfers, with a 3% to 5% transfer fee. Moving a $6,000 balance off a 24.99% card onto a 0% card for 18 months saves roughly $1,350 in interest even after the transfer fee.
2. Call the issuer and ask. On a long-standing account in good standing, credit card companies will often drop your APR by 2 to 5 points on request, especially if you mention a competing balance transfer offer. Ten minutes on the phone can save hundreds.
3. Debt consolidation loan. Personal loans from SoFi, LightStream, or a local credit union typically run 8% to 15% for borrowers with decent credit, versus the 20%+ you are paying on cards. A single fixed monthly payment also simplifies the math and forces a payoff timeline.

When Consolidation Helps, When It Hurts

A debt consolidation loan helps when the new APR is materially lower than the weighted average of your current debts, the new payment is one you can actually afford for the full term, and you stop using the old credit cards. It hurts when you keep charging new purchases on the now-empty cards, when the loan extends your payoff timeline by several years just to lower the monthly payment, or when the origination fee (1% to 8% of the loan) plus closing costs cancel out the APR savings.

The hidden risk of consolidation is behavioral, not mathematical. Roughly 40% of consolidation loan borrowers run their card balances back up within two years, according to a 2023 TransUnion study. If you take this route, close or freeze the old accounts after transfer.