Debt Payoff Calculator
Compare two ways to allocate a fixed monthly debt budget: paying the highest-rate debt first or paying the smallest balance first. The useful comparison holds the budget constant, so you can see the effect of payment order rather than accidentally comparing different spending commitments.
Both methods use the same budget, pay minimums first, and roll freed cash to the next target.
Build a complete starting list
For each debt, enter a label, current balance, annual interest rate, and required monthly payment. Then enter the total amount you can devote to these debts each month, including required payments.
Use generic labels such as “Card A.” Account numbers or identifying information are unnecessary.
The model first covers every active debt's entered minimum payment, capped at the amount needed to clear it. It sends the remaining budget to the target debt. Once a debt is cleared, unused payment money moves to another debt, including within the same modeled month.
Compare the two payment orders
The avalanche method prioritizes the highest rate. The snowball method prioritizes the smallest balance. The CFPB describes the potential trade-off: interest savings versus the encouragement of clearing smaller debts sooner. CFPB repayment worksheet
Here is a hypothetical example with a fixed $300 monthly budget:
In this model, avalanche saves $199.63. Your result depends on the balances, rates, payment obligations, and budget you enter. The example does not assign a dollar value to motivation or predict whether a particular strategy will be easier for you to maintain.
| Debt | Starting balance | APR | Entered minimum |
|---|---|---|---|
| Smaller debt | $1,000 | 10% | $25 |
| Larger debt | $4,000 | 25% | $100 |
| Strategy | Payoff time | Total interest | Total paid |
|---|---|---|---|
| Avalanche | 20 months | $949.89 | $5,949.89 |
| Snowball | 21 months | $1,149.52 | $6,149.52 |
Understand the assumptions
Interest is approximated monthly using APR/12 and rounded to cents. Minimum payments stay at the dollar amounts you enter until a debt needs less to be paid off. The total budget stays constant. There are no new purchases, new fees, rate changes, promotions, or missed payments.
Real minimums often change. Update the inputs as statements arrive. For debt with a promotional expiry, collateral risk, arrears, or special repayment obligations, a simple rate-order comparison may not identify the right priority.
If the budget is below required payments, the calculator returns that problem instead of allocating an unaffordable plan. If repayment runs beyond the modeled limit, it reports the remaining balance and does not claim a completed payoff.
What to do with the result
Choose a budget you can repeat after essential expenses. Then compare the strategies at that budget. A faster projected result is useful only if you can actually make the payments.
If minimum payments are already unaffordable, contact the creditors about options and consider a reputable credit counselor. Counseling and debt settlement are different services with different risks. CFPB comparison
For a single revolving balance, use the credit card interest calculator. For a proposed installment loan, use the loan payment calculator.