Debt Payoff Calculator · Practical guide
Debt Payoff Calculator with Extra Payments
Extra payments go straight to principal — even $100 a month can move your debt-free date up by over a year.
At a glance
Quick answer
Adding extra money to your monthly debt payment is the single fastest lever you control: on $20,000 of mixed debt, an extra $200 per month shortens the payoff from 57 months to 36 and saves about $3,852 in interest.
Interactive tool
Debt Payoff Calculator
Enter your own values, then compare the result with the examples below.
Summary
Payoff Order
| Order | Name | Payoff Month | Interest Paid |
|---|
Month-by-Month Projection
| Month | Payment | Interest | Principal | Remaining Balance |
|---|
Worked Example: $20,000 Across Three Debts
Suppose you owe $8,000 on a card at 19.99% APR ($200 minimum), $5,000 on a card at 16.99% ($125 minimum), and $7,000 on a car loan at 6% ($175 minimum). Here is what different extra payments do under an avalanche plan:
| Extra per month | Payoff time | Total interest |
|---|---|---|
| $0 | 57 months | $8,144 |
| $100 | 43 months | $5,571 |
| $200 | 36 months | $4,292 |
| $300 | 30 months | $3,502 |
Why Extra Payments Punch Above Their Weight
Extra funds are applied to principal after all minimums are met, so they reduce the balance that interest is charged on every remaining month. And when a debt is paid off, its minimum payment rolls into the extra amount — a $200 extra payment can quietly grow into a $400+ payment late in the plan.
How to Find the Extra Money
- Redirect one subscription or streaming service per month.
- Send half of any raise or bonus to the target debt before it hits your budget.
- Round each minimum up to the nearest $50.
Enter your own balances, APRs, and minimums above and sweep the extra-payment field until the payoff month lands where you want it.
Frequently Asked Questions
Does an extra payment go to interest or principal?
After each debt's minimum payment is made, all extra money is applied to the target debt's principal. That is what makes extra payments so effective — none of it is lost to that month's interest.
Should I make one big extra payment or spread it monthly?
Sooner is better because interest accrues monthly on the remaining balance. A $1,200 lump sum today saves slightly more than $100 per month for a year, but either approach beats minimums only.
Is there any reason not to pay extra on debt?
Keep a small emergency fund first so one surprise expense does not push you back onto the cards. Also check that no loan charges a prepayment penalty, though most consumer debts in the US do not.
What happens to my extra payment when a debt is paid off?
The freed-up minimum is added to your extra amount, and the combined total attacks the next target debt. This rollover is the engine behind both snowball and avalanche plans.