Is this how my bank calculates it?

Close, not identical. Banks charge a daily rate on an average daily balance, and their minimum-payment formulas vary. This calculator uses a fixed APR, interest added monthly on the remaining balance, the same payment every month and no new purchases. Once you connect a card in the app, your statements' own figures replace these assumptions.

What should I enter for the APR?

Your card's purchase APR, printed on your statement under the interest charge calculation. If the card is on a 0% promotion, enter 0 for the months it lasts, then the regular rate.

Why does a small extra payment move the date so much?

Every extra dollar goes straight to the balance, and the balance is what next month's interest is charged on. The effect compounds in your favor each month, which is why the gap between the two dates is usually bigger than the extra alone would suggest.

Is this financial advice?

No. It is arithmetic on the numbers you entered: information and education, not financial, legal or tax advice. For a big decision, talk to a qualified professional.

Calculator

Debt-free date calculator

Enter a balance, its APR and what you pay each month. Slate names the month you're done and the interest on the way, then shows what adding a little each month does to both. The same arithmetic as the app, rounded to the cent every month.

Balance

APR

You pay a month

Extra each month

Done by

That's 2 years and 11 months. The bank collects about $2,053.53 in interest on the way.

Interest the bank doesn't get: $1,324.52
Sooner than now: 20 months

Slate does this for each card it tracks, from your real statements.

Assumes a fixed APR, interest added monthly on what's left, the same payment every month and no new purchases. An estimate, not financial advice. Once you connect, your statements' figures replace these. How Slate does the math

From today to debt-free

How to read it

Done by: The month the balance reaches zero at the payment you entered plus the extra on the slider, if interest is added monthly on what's left and nothing new goes on the card.
Interest the bank doesn't get: The total interest on your current payment minus the total at the higher payment. It is money you keep, not money you earn, which is why it's shown in sage rather than as a gain.
From today to debt-free: One bar per month (grouped when the payoff is long). The ink part of each bar reaches the balance; the cyan part is the bank's interest, and it shrinks as the balance falls. The empty stretch to the right is the time the extra wins back.
When no date appears: A payment that doesn't cover the first month's interest never pays off the balance. Slate says so rather than showing a date decades away.

Slate does this for your real cards.

Connect a card, read-only through Plaid, and these figures come from your own statements: each card you track, every purchase, and a date you can move. In development for iPhone. The App Store listing goes up when it ships.

Questions

Is this how my bank calculates it?: Close, not identical. Banks charge a daily rate on an average daily balance, and their minimum-payment formulas vary. This calculator uses a fixed APR, interest added monthly on the remaining balance, the same payment every month and no new purchases. Once you connect a card in the app, your statements' own figures replace these assumptions.
What should I enter for the APR?: Your card's purchase APR, printed on your statement under the interest charge calculation. If the card is on a 0% promotion, enter 0 for the months it lasts, then the regular rate.
Why does a small extra payment move the date so much?: Every extra dollar goes straight to the balance, and the balance is what next month's interest is charged on. The effect compounds in your favor each month, which is why the gap between the two dates is usually bigger than the extra alone would suggest.
Is this financial advice?: No. It is arithmetic on the numbers you entered: information and education, not financial, legal or tax advice. For a big decision, talk to a qualified professional.

Sources

3How a card company calculates the interest you owe: a daily periodic rate applied to an average daily balance, with separate APRs for purchases, cash advances and balance transfers. Consumer Financial Protection Bureau. Checked October 3, 2026.
4What the minimum-payment box on a statement means, and why paying more than the minimum shortens the payoff and lowers the interest. Consumer Financial Protection Bureau. Checked October 3, 2026.

Every other figure on this page is an example, computed with the same arithmetic the app uses. Cited figures are re-read from their release each time it updates.