Debt Payoff Calculator

See how long until you are debt-free and how much interest you will pay. Raise the payment to see it shrink fast.

How the Debt Payoff Calculator works

Enter one debt's balance, its APR and the fixed amount you will pay each month. The calculator runs the debt month by month: it adds a month of interest (balance × APR ÷ 12), subtracts your payment and repeats until the balance reaches zero. It reports the months, total interest and total paid; the last payment is just what is left.

The same answer comes from a formula: Months = −ln(1 − B × i ÷ P) ÷ ln(1 + i), where B is the balance, P the monthly payment and i the monthly rate. On $8,000 at 19%, i = 0.0158333, so the first month's interest is $126.67.

If your payment is at or below the first month's interest, the debt never clears and the calculator tells you so. With several debts, enter each one separately; the strategies below explain which to target first.

Example calculation

Example 1 - one debt, the power of a bigger payment. You owe $8,000 at a 19% APR. At a $200 monthly payment, the calculator runs 64 months and racks up $4,773.54 in interest (the formula returns 63.87 months, which rounds up to the 64th payment). Now raise the payment to $350: payoff drops to 29 months and interest falls to $2,010.26. Adding $150 a month clears the debt 35 months sooner and saves $2,763.28 - the single biggest lever you control.

This calculator handles one debt at a time. Examples 2 and 3 were worked month by month to show how payoff order changes the cost across several debts.

Example 2 - avalanche vs snowball on three debts. You have a $2,500 card at 25.99%, a $7,000 card at 18%, and a $4,000 loan at 6.5% (total $13,500), with $600 a month to spend. The avalanche attacks the 25.99% card first and clears everything in 27 months for $2,286.01 interest. The snowball attacks the $2,500 balance first; it also finishes in 27 months but costs $2,601.17 - $315.16 more - because it lets the 25.99% card keep accruing longer.

Example 3 - why minimum-only payments fail. Keep the same three debts but pay only the fixed minimums on each ($75 + $175 + $100 = $350 total, with no rollover): the slowest debt drags the picture out to 62 months and $6,271.08 in interest. Versus the avalanche, paying minimums costs an extra 35 months and $3,985.07.

Plan	Monthly outlay	Months to debt-free	Total interest	Total paid
Minimums only (no rollover)	$350	62	$6,271.08	$19,771.08
Snowball	$600	27	$2,601.17	$16,101.17
Avalanche	$600	27	$2,286.01	$15,786.01

Same $13,500 of debt, three very different outcomes. The jump from minimums to a fixed $600 budget saves the most; the choice between avalanche and snowball is the fine-tuning on top.

Tips for using the Debt Payoff Calculator

• Work backward from a date: pick 24 months, then raise the payment until the calculator shows 24. The table below shows the payments for an $8,000, 19% debt.
• Keep paying at least the minimum on every other debt while you target one.
• When one debt is gone, add its payment to the next one instead of spending it.
• Put windfalls straight onto the highest-APR balance: $2,000 off a $12,000, 19% balance at $400 a month clears it 9 months sooner and saves about $1,576 of interest.
• Treat a 0% balance transfer as a deadline: set a payment that clears the balance plus the fee before the promo ends.

Avalanche vs snowball: which debt to attack first

The avalanche method pays the highest-APR debt first and is mathematically the cheapest; the snowball method pays the smallest balance first and is the most motivating. Both pay minimums on everything else and throw all spare money at one target.

The difference is purely the order. Avalanche minimizes interest because it kills your most expensive dollars first. Snowball minimizes the time to your first win - clearing a small balance fast gives a psychological boost that keeps many people in the game. Using the three debts from Example 2 above:

	Avalanche	Snowball
Attacks first	Highest APR (25.99%)	Smallest balance ($2,500)
Best at	Lowest total interest	Fastest first payoff / motivation
Total interest	$2,286.01	$2,601.17
Months to debt-free	27	27
Extra cost vs avalanche	$0	$315.16

Here the timelines happen to match and the gap is only $315 - that is common when the highest-APR debt is also fairly small. The wider your balances and rates spread, the more avalanche pulls ahead. Pick avalanche if you are driven by the math; pick snowball if you have abandoned payoff plans before and need momentum. Either beats doing nothing. If a single card is your real problem, the credit card payoff calculator drills into one revolving balance.

Why minimum-only payments are a trap

Paying only the minimum keeps you in debt for years because most of each payment goes to interest, not principal. Example 3 above is the proof: the same $13,500 takes 62 months and $6,271 in interest when you only cover the minimums, versus 27 months and $2,286 once you commit a fixed $600 and roll freed payments forward.

The trap deepens with percentage-based minimums (often around 2% of the balance, or 1% plus interest) because as the balance falls the required minimum falls too - so your payment shrinks just when you should keep pushing. That declining payment is exactly why a single revolving balance can linger past a decade. The strategy fix for any debt is the same: lock a fixed-dollar total and never let it drop, even as individual balances disappear, and keep redirecting each freed payment onto the next target. The size of your payment matters far more than which method you choose - moving from minimums to a real budget is the big win; avalanche vs snowball is the tweak. For the issuer-side mechanics of how a card's shrinking minimum is calculated, see the credit card minimum payment calculator.

Debt-free by a date: the payment you need

To clear a debt by a set date, pay PMT = B × i ÷ (1 − (1 + i)⁻ⁿ) each month, where n is the number of months you want. For $8,000 at 19% APR:

Debt-free in	Monthly payment	Total interest
12 months	$737.25	$847
24 months	$403.27	$1,678
36 months	$293.25	$2,557
48 months	$239.20	$3,482

Enter any of these payments above and the calculator returns the matching month count. In a spreadsheet: =PMT(0.19/12, 24, -8000).

How to build the math by hand or in Excel

You can reproduce the single-debt payoff with one spreadsheet function: NPER. It returns the number of payments for a given balance, rate, and payment.

The formula is:

=NPER(APR/12, -payment, balance)

For the $8,000 debt at 19% with a $350 payment, =NPER(0.19/12, -350, 8000) returns 28.6, which rounds up to 29 months - matching the tool. The payment is entered as a negative because it is cash leaving your pocket. To get the cost:

• Total paid: =payment * NPER(APR/12, -payment, balance)
• Total interest: =(payment * NPER(APR/12, -payment, balance)) - balance

To flip the question and find the payment that hits a target date, use =PMT(APR/12, target_months, -balance). By hand, the one risky step is the natural log in n = -ln(1 - (B x i) / P) / ln(1 + i): compute (B x i) / P first, subtract from 1, then take ln of both that result and (1 + i). A multi-debt avalanche or snowball plan cannot live in a single cell - it needs a month-by-month table where each cleared debt's payment is added to the next. Here, run each debt separately and move freed-up payments to the next one.

Debt payoff time and interest: a $15,000 reference grid

This quick-reference shows how long $15,000 takes to clear, and the total interest paid, at three common APRs and three monthly payments. Every figure is recomputed by month-by-month simulation (interest = balance x APR / 12 each month). Two patterns stand out: a higher payment cuts both time and interest sharply, and at 24% APR a $300 payment never clears the debt because $15,000 x 24% / 12 = $300 of interest in the first month, so the payment exactly equals the interest and nothing touches principal.

APR	$300/month	$500/month	$700/month
12%	70 mo / $5,899 interest	36 mo / $2,923	25 mo / $1,966
18%	94 mo / $12,934	41 mo / $5,077	27 mo / $3,231
24%	Never pays off	47 mo / $8,137	29 mo / $4,783

Takeaway: on the 18% row, raising the payment from $300 to $700 saves about $9,703 in interest and 67 months. The lesson the grid drives home is that on high-rate debt the payment size, not the strategy label, is what bends the curve. Model your exact balance and rate at the top of this page.

Advanced moves: lump sums, transfers, and consolidation

Three tactics can compress your timeline beyond just raising the monthly payment: one-time lump sums, balance transfers, and a consolidation loan.

• Lump sums: a tax refund or bonus applied to your highest-APR balance cuts both the principal and every future interest charge on it. Model it by lowering that debt's starting balance, not the payment - a $2,000 windfall on a $12,000 balance at 19% trims roughly 9 months and over $1,500 of interest.
• Balance transfers: moving a 25% card to a 0% promo can route nearly your whole payment to principal during the promo window. Set a payment that clears the balance before the promo ends, and weigh the transfer fee (often 3-5%).
• Consolidation: replacing several high-rate debts with one fixed loan can lower your blended rate and simplify the plan - but only if the new APR is genuinely lower and you do not stretch the term. Compare the new loan in the loan calculator against your current avalanche plan from this page.

Each tactic changes one input. The discipline that makes any of them work is unchanged: keep the freed-up cash inside the payoff, never back in your spending.

Common mistakes to avoid

Most debt-payoff plans fail not on the math but on a handful of avoidable behaviors.

• Letting the payment shrink as balances fall. The biggest killer. Lock a fixed-dollar total and hold it until the last debt is gone.
• Not rolling freed payments forward. When debt one is cleared, its payment must move onto debt two. Pocketing it restarts the slow grind.
• Sorting by balance when you mean to save money. Attacking the biggest balance feels productive but can ignore a smaller, higher-APR debt that costs more per dollar - that is the avalanche's whole argument.
• Missing a minimum on a back-burner debt. Late fees and penalty APRs can wipe out a month of progress elsewhere.
• Ignoring the never-pays-off warning. If a payment is at or below that debt's monthly interest, no amount of time clears it - the balance grows.
• Treating a 0% transfer as free. The promo is a deadline. Plan to finish before the rate snaps back, and account for the transfer fee.

What this tool covers (and when to use a sibling)

This calculator plans one fixed-rate debt at a time: enter the balance, APR and a fixed payment to see the payoff date and the interest. For several debts, run each one here, then use the avalanche or snowball order above to decide where extra money goes.

• One credit card, with daily-interest and balance-transfer details: credit card payoff calculator.
• How a card's shrinking minimum works: minimum payment calculator.
• Whether your income can carry the debt: debt-to-income calculator.

Once you are debt-free, send the same monthly amount to the emergency fund calculator goal, then the savings goal calculator.

Related on this site

credit card payoff calculator · minimum payment calculator · loan calculator · debt-to-income ratio calculator · emergency fund calculator

Debt Payoff Calculator — frequently asked questions

How much faster do I pay off $10,000 at 22% APR if I pay $400 instead of $250 a month?

Raising the payment from $250 to $400 a month cuts payoff from about 73 months to 34 months and slashes interest from roughly $8,189 to $3,500 on a $10,000 balance at 22% APR.

That extra $150 a month saves around $4,689 in interest and over three years of payments. The pattern is universal: a higher fixed payment is the single biggest lever on any debt. Model your own numbers in the debt payoff calculator.

What payment do I need so a $6,000 balance at 24% APR actually goes down?

You must pay more than the monthly interest, which on $6,000 at 24% APR is exactly $120 ($6,000 x 0.02). A $120 payment never reduces the balance at all.

At $130 a month it does eventually clear, but takes about 130 months and roughly $10,839 in interest. The lesson: any payment at or below monthly interest is a permanent treadmill. Use the debt payoff calculator to find your floor.

How do I calculate months to pay off a debt by hand?

Use the formula n = -ln(1 - rB/P) / ln(1 + r), where B is the balance, P the monthly payment, and r the monthly rate (APR / 12, as a decimal).

Example: $12,000 at 16% gives r = 0.013333. For P = $350: -ln(1 - 0.013333 x 12,000 / 350) / ln(1.013333) = about 46.1, so 47 months. A simulation confirms 47 months and roughly $4,143 interest. If 1 - rB/P is zero or negative, the payment never clears the debt.

How much does paying $600 instead of $400 save on a $20,000 loan at 18% APR?

Paying $600 a month instead of $400 on $20,000 at 18% APR cuts payoff from about 94 months to 47 months - exactly half the time.

Interest drops from roughly $17,245 to $7,934, a saving of about $9,310. Notice the interest at $400 nearly equals the loan itself; at 18% APR, a slow payment almost doubles your cost. Adding 50% to the payment more than doubles the speed.

How much sooner does a $2,000 lump-sum payment clear $12,000 at 19% APR?

Applying a $2,000 windfall to a $12,000 balance at 19% APR, while keeping $400 a month, finishes the debt about 9 months sooner - 33 months instead of 42.

Interest falls from roughly $4,407 to $2,831, a saving near $1,576 on top of the $2,000 you paid. Lump sums work best applied to your highest-APR balance, the avalanche principle in action. Test windfalls in the debt payoff calculator.

Is it better to pay off the highest-rate debt or the one with the smallest balance?

Pay the highest-rate debt first if you want the lowest total cost; pay the smallest balance first if you need early wins to stay consistent.

With a $1,000 debt at 12% and a $6,000 debt at 26% on $300 a month, highest-rate-first (avalanche) costs about $2,446, while smallest-first (snowball) costs about $2,781 - a $335 gap. Pick avalanche for math, snowball for behavior; the difference shrinks when balances are similar.

Guides & articles

• Avalanche vs Snowball: Which Debt Should You Pay Off First?
• Why Paying More Than the Minimum Clears Debt Far Faster

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