Pay off multiple debts by putting extra money toward the highest APR first. Enter each balance, APR, and minimum payment to estimate payoff time and total interest.
How to use this calculator
- Set “Extra payment per month” if you can pay more than the minimums. This extra gets sent to one debt at a time.
- Add your debts. For each debt, enter:
- Balance (how much you owe)
- APR (interest rate per year)
- Minimum payment (the smallest payment you will pay each month on that debt)
- If you accidentally added a debt, use the “x” button on that debt card to delete it.
- Open “Advanced options” if you want:
- A start month to show an estimated debt-free month
- A max months limit (stops the math after a cap)
- The daily interest estimate toggle (roughly models cards that accrue interest daily)
- Press “Calculate”.
- Read the results:
- Time to debt-free: how long until all balances reach $0
- Total interest paid: how much interest you pay across all debts
- Payoff order: which debts get attacked first (highest APR first)
- Balance chart: total balance dropping over time
- If the payoff time is too long, increase the extra payment, increase minimums, or reduce new borrowing.
Reality check: creditors can set minimum payments using their own formulas, rates can change, and fees are not modeled unless you add them into balances or payments.
Definitions
- Debt avalanche: pay minimums on every debt, then send all extra money to the highest APR debt until it is paid off, then repeat.
- Balance: how much you owe right now.
- APR: annual percentage rate (yearly interest rate as a percent).
- Minimum payment: the smallest payment you will make each month on a debt.
- Extra payment: money above minimums that is targeted to one debt at a time.
- Debt-free date: the month when all balances reach $0 (only shown if you set a start month).
- Daily interest estimate: a simplified way to estimate interest using APR divided by 365 and an average month length.
This month-by-month simulation keeps your starting monthly budget fixed: initial minimum payments plus Extra payment per month. After each minimum is paid, all remaining budget goes to the highest APR debt. When a debt is paid off, its freed payment rolls to the remaining debts, including unused funds in that same month. The final payment can be smaller than the budget.
At the start of each simulated month, the calculator looks at debts with a remaining balance and sorts them by APR (highest to lowest). If two APRs tie, it uses the higher balance first as a tie-break.
Your extra payment is applied to the top debt until that debt is fully covered for the month (balance plus that month’s interest), then any remaining extra rolls to the next debt in the sorted list.
By default, monthly interest is estimated with a monthly periodic rate:
r = (APR / 100) / 12 and interest = balance * r.
If you enable “daily interest estimate”, it uses:
interest = balance * (APR / 100) * (30.4375 / 365).
The 30.4375 value is an average month length in days, so this is still an estimate.
Real lenders and card issuers often use daily periodic rates and statement-cycle timing. Your actual results can differ.
- Find active debts (balance greater than $0) and sort them by APR for avalanche priority.
- For each active debt: estimate that month’s interest from the current balance.
- Set the planned payment for each debt to the minimum payment you entered, capped at (balance + interest).
- Allocate the starting budget remaining after this month’s minimums to debts in descending APR order, including minimum payments freed by earlier payoffs.
- Apply each debt’s payment: principal paid = payment – interest. If principal is not positive, the balance increases by the unpaid interest for that month.
- If a debt reaches $0, the calculator records the month it was paid off and removes it from future months.
- “Debt-free in” is the number of simulated months until every balance reaches $0.
- “Total interest paid” is the sum of estimated interest across all debts over the simulation.
- “Monthly budget used” is the sum of your entered minimum payments (for debts with balances) plus your extra payment.
- “Payoff order” shows the order debts reached $0 under the avalanche strategy.
- “Compared to minimum payments only” uses the entered fixed minimum on each remaining debt, no extra payment, and no rollover of freed payments. That comparison budget declines as debts are paid off. The main avalanche keeps the starting budget fixed.
- No fees are modeled (late fees, annual fees, penalty APR triggers, transfer fees).
- No promotional APR periods or APR changes over time.
- Minimum payments are treated as fixed dollar amounts you enter. Many issuers use formulas that change with balance and interest.
- For credit cards, payment allocation rules within a single account can be more complex when multiple APR “buckets” exist.
- Timing is simplified: interest is estimated once per month and payments are applied once per month. Real interest accrues daily and payments post on specific dates.
- The “debt-free date” is a calendar estimate based on your chosen start month. It does not know your statement cycle dates.
- CFPB: “Your Money, Your Goals” toolkit (Module 6 includes “pay highest interest rate first” strategy)
- CFPB Regulation Z (12 CFR 1026.7): periodic statement disclosures, including periodic rates and balance computation concepts
- CFPB Regulation Z (12 CFR 1026.53): allocation of payments rules for credit card accounts
- CFPB Ask CFPB: grace periods and when interest may be charged