Should I pay off debt or build an emergency fund first?

Most financial experts recommend a small emergency fund ($1,000) before aggressively attacking high-interest debt. Without a buffer, any unexpected expense forces you to reach for the credit card, undoing your progress. Once you have that cushion, direct every extra dollar at high-interest debt — the guaranteed 'return' on paying off a 22% credit card beats almost any investment.

Can I model a one-time bonus or tax refund?

Yes — use the Windfall scenario in the Scenarios panel. Enter the month you expect the payment and the amount. The calculator will show how it accelerates your debt-free date and reduces total interest. You can add multiple windfalls.

Does this calculator work for mortgages and student loans?

Yes. Enter the remaining balance, the current APR (not the original rate if you refinanced), and the current minimum payment. The simulation works for any debt with a balance and interest rate, including mortgages, student loans, personal loans, car loans, and 0%-APR family loans.

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Debt Payoff Calculator

Q: What is the difference between the debt snowball and debt avalanche?

Both methods pay minimums on all debts and focus extra money on one debt at a time. The avalanche directs extra money to the highest-APR debt first, minimizing total interest paid. The snowball directs extra money to the smallest balance first, creating quick wins that boost motivation. Mathematically the avalanche is almost always cheaper; psychologically the snowball can keep you on track if small wins matter to you.

Q: What is a debt death spiral?

A death spiral occurs when your minimum payment is less than the monthly interest charge. The balance grows every month even though you're making payments. The calculator flags this automatically and tells you the minimum payment needed to escape it.

Q: Does a balance transfer actually save money?

It depends on the fee, your repayment speed, and the new APR. A 3% balance transfer fee on a $5,000 balance costs $150 upfront. If the new card has 0% for 18 months and you pay it off in that window, you save 100% of the interest that would have accrued. Use the Scenarios panel in this calculator to model the exact numbers for your situation.

Q: How much does an extra $100 per month actually save?

It depends on your balance and APR, but the effect is dramatic. On a $10,000 credit card at 22% APR with a $200 minimum, adding $100/month reduces payoff from about 137 months to 52 months and saves around $11,800 in interest. Use the comparison bars to see the exact impact for your debts.

Enter your debts, choose your strategy, and see exactly when you'll be debt-free — and how much interest you'll save. Model windfalls, balance transfers, and income changes.

Start with a template:

Your Debts

Payoff Strategy

Avalanche Method

Pay minimums everywhere. Focus all extra money on the highest-APR debt first.

Best for: minimizing total interest paid.

Snowball Method

Pay minimums everywhere. Focus all extra money on the smallest balance first.

Best for: motivation and quick early wins.

Extra monthly payment — $0 above minimums

Even $50–100/month extra dramatically cuts payoff time and total interest.

Scenarios (optional)

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months to debt-free

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total interest paid

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interest saved vs min payments

Debt-free by: —

Balance Over Time

Time to payoff — extra payment comparison

Min payments only

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Your plan

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+$50/mo extra

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+$100/mo extra

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How debt payoff math actually works

Every month, your lender multiplies your remaining balance by your monthly interest rate (APR ÷ 12) to calculate that month's interest charge. That charge is added to your balance before your payment is applied. This is the mechanic that makes debt so persistent.

For example, a $5,000 credit card at 22.99% APR charges $95.79 in interest in month 1. If your minimum payment is $100, only $4.21 pays down the principal. At that rate, it would take more than 13 years and cost about $11,700 in interest to pay off. Bump the payment to $200/month and it's done in under 3 years with about $1,900 in interest — roughly an 84% reduction in total interest from one simple change.

Why minimums keep you in debt so long

Card minimums are deliberately low — typically about 1% of the balance plus that month's interest, or a small flat floor (around $35). Paying only the minimum can stretch a balance out for a decade or more, with most of your money going to interest, not principal. This calculator lets you set the real minimum (or any fixed payment) for each card and see the true payoff timeline — and how much sooner even a small extra payment gets you out.

The snowball vs. avalanche decision

Both methods pay minimums on all debts and focus every extra dollar on one debt at a time. They differ only in how they choose the "focus" debt:

	Avalanche	Snowball
Focus debt	Highest APR first	Smallest balance first
Total interest paid	Minimum possible	Usually slightly more
First payoff	Sometimes slower	Fast — quick psychological win
Best for	Maximizing savings if you'll stick to the plan	Keeping motivation if you need visible wins
Difference in practice	Usually $200–$2,000 depending on the debt mix. Use this calculator to see the exact gap for your numbers.

How extra payments compound over time

Extra payments don't just reduce next month's interest — they permanently lower the balance against which every future month's interest is calculated. A $100 extra payment in month 1 saves approximately $100 × APR in interest over the remaining life of the loan — sometimes several times over on a long high-rate debt. This is why financial advisors consistently rank eliminating high-interest debt as one of the highest-return "investments" available.

Windfalls: the fastest debt-payoff accelerator

A one-time lump-sum payment — tax refund, work bonus, inheritance, sale of an asset — can have a disproportionate impact because it hits the balance early, when the remaining term (and therefore the interest at risk) is longest. A $2,000 windfall applied in month 3 to a high-rate card might save $3,500 in interest over the remaining payoff. Use the Windfall scenario above to see the exact math for your situation.

Balance transfers: when the math works

A balance transfer moves a balance to a new card with a lower APR — often a 0% promotional rate for 12–21 months. The upfront fee (typically 3–5%) is the cost of the arbitrage. The deal makes sense when: the fee is less than the interest you'd pay in the same period at the original rate; and you can realistically pay it off before the promotional period ends. If you can't pay it off in time, the reverted APR (often 25%+) may erase the gains. Model it with the Balance Transfer scenario above — the calculator adds the fee to the starting balance and resets the APR at the specified month.

Frequently asked questions

What's the difference between the debt snowball and debt avalanche?

Both methods pay minimums on all debts and direct extra money to one debt at a time. The avalanche targets the highest-APR debt first (minimizing total interest paid). The snowball targets the smallest balance first (building momentum through quick wins). Mathematically the avalanche is almost always cheaper; psychologically the snowball can be easier to sustain. Use this calculator to see the exact dollar difference for your specific debts.

How is monthly interest calculated?

Monthly interest = balance × (APR ÷ 12). For a $5,000 balance at 22.99% APR: $5,000 × (0.2299 ÷ 12) = $95.79 in month 1. This is charged before your payment is applied, so a $100 minimum only puts $4.21 toward principal. This calculator uses this exact formula — the same math your lender uses — for every debt in every month.

What is a debt death spiral?

A death spiral occurs when the monthly interest charge exceeds the minimum payment. The balance grows every month even while you're making payments. The calculator detects this automatically and shows a warning. To escape it, you need to increase your payment to at least cover the monthly interest (balance × APR / 12), then start adding more to reduce the principal.

Does a balance transfer actually save money?

It depends on the fee, the new APR, and how quickly you repay. A 3% fee on a $5,000 balance costs $150 upfront. If the promo rate is 0% for 18 months and you pay it off in that window, you save all of the interest that would have accrued. Use the Balance Transfer scenario in this calculator — it adds the fee to the balance and resets the APR at the specified month so you see the true net outcome.

How much does an extra $100 per month actually save?

It depends on your balance and APR, but the effect is substantial. On a $10,000 credit card at 22% APR with a $200 minimum, adding $100/month reduces payoff from roughly 137 months to 52 months and saves about $11,800 in interest. Check the comparison bars on the right — they show the exact impact for your specific debts.

Can I model a tax refund or bonus?

Yes — use the Windfall scenario. Enter the month you expect the payment and the amount. You can add multiple windfalls (say, a tax refund every April) and see the cumulative effect on your debt-free date. The calculator distributes the windfall using the same strategy priority as your regular extra payment.

Does this calculator work for mortgages, car loans, and student loans?

Yes — for any debt with a remaining balance and an interest rate. Enter the current balance (not the original amount), your current APR, and your regular payment. The simulation is mathematically identical regardless of debt type.

Should I pay off debt or invest first?

For high-rate debt (above 7–8%), paying it off typically beats investing because the guaranteed "return" on a 22% credit card is 22%. For lower-rate debt (federal student loans, mortgages), the math is closer — contributing to an employer 401(k) match first almost always wins, since the match is a 50–100% immediate return. Most advisors recommend: get the 401(k) match → small emergency fund → attack high-rate debt → build broader savings.

Can I save and share my scenario?

Yes — the "Copy link" button encodes your exact debts and settings into the URL. Anyone with the link (including future-you from a bookmark) can load the exact same scenario. Your last calculation is also saved automatically in your browser so it's still there when you come back.

How do I track my progress after calculating?

Click "Track this plan in LazeeFish." LazeeFish is an envelope budgeting app that can pre-fill your debt envelopes with the numbers from this calculator. Connect your bank and actual payments update your balance automatically — so you always know exactly how your real payoff compares to this plan.