Clear path out of debt.
Free calculators that line up your real payoff date, the interest you'll actually pay, and what every extra dollar saves you. No signup. No ads. No email capture. Every formula is on the page.
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Twelve calculators, grouped by the question that brought you here. Each one shows its math. Open one, plug in your numbers, see your real payoff date.
When will it be paid off?
Single-loan payoff math. Pick the one that matches your loan type.
- 01Loan Payoff DateGeneric fixed-APR loan — personal, HELOC, anything not below.
- 02Credit Card PayoffTuned for revolving credit and high APRs.
- 03Auto Loan PayoffDaily simple-interest accrual the way auto lenders actually work.
- 04Student Loan PayoffFederal vs private, IDR cap, grace-period capitalization.
- 05Personal Loan PayoffFixed-rate amortizing — see months and interest saved from extra-to-principal.
How can I pay it off faster?
Find the leverage in your existing loan without refinancing.
I have multiple debts — what order?
Multi-debt portfolio simulators. All three model rollover payments correctly.
Snowball, avalanche, and the third option. Avalanche attacks the highest APR first and pays the least interest. Snowball attacks the smallest balance first and delivers an earlier win that keeps some people on the plan. The strategy you actually stick with beats the silent default — paying minimums forever.
What a credit card minimum really does. A typical minimum is the interest charge plus about 1% of principal — on a $5,000 balance at 24% APR, near $110 of which $100 is interest. Principal moves about $10 per month, which is why minimum-only payoff timelines routinely run past 20 years.
When extra payments help most. Always early. $100 per month applied in month 1 of a thirty-year loan saves several times the interest of $100 per month applied in month 100, because the balance — and the interest accruing on it — is highest at the start. Extra Payment Savings shows the gap on your loan.
Refinance vs. consolidate. Refinancing replaces a loan with a cheaper version of itself when rates drop or your credit improves. Consolidation merges several debts into one. Both can save money — and both can quietly cost more if the new term outruns what was left on the old debt.
Short explainers that pair with the calculators above.
- Snowball vs AvalancheWhich method saves more money — and which gets you to debt-free.
- How Credit Card Interest WorksAverage daily balance, daily periodic rate, and what the grace period really protects.
- When Consolidation Makes SenseA decision framework with a worked break-even example.
- Paying Extra on PrincipalWhy early extra payments save more, with a table at 7% / 15% / 22% APR.
- How to Pay Off Debt FastSix strategies that actually work — budgeting, payoff order, extra principal, and income.
- Debt-to-Income RatioFree DTI calculator with lender bands at 36% and 43%.
- The Minimum Payment TrapWhy card minimums stretch a $5,000 balance into decades — and what 2x or 3x clears it in.
The DebtMath ledger
Why DebtMath?
- The math is visible. Every page documents the formula it uses. Verify the answer in a spreadsheet if you want to.
- The defaults aren't pretending. Auto loans use daily simple interest. Student loans handle IDR caps and grace-period capitalization. Bi-weekly handles 26 periods per year correctly.
- No accounts, no email capture, no ads. Standard analytics only. Run a calculator and close the tab.
Should I use the debt snowball or the debt avalanche?
Avalanche pays less total interest because it eliminates the highest-APR debt first. Snowball delivers an earlier first win, which helps some people stay on the plan. Pick avalanche if you've stuck with budgets before; pick snowball if you've fallen off them.
Will paying more than the minimum on my credit card hurt my credit score?
No. Paying more lowers your balance, which lowers your utilization ratio — one of the largest inputs to a FICO score. There is no penalty for prepaying revolving debt.
How is credit card interest actually calculated?
Most U.S. issuers use the average daily balance method with daily compounding: each day, the issuer applies the daily periodic rate (APR ÷ 365) to the prior day's balance, so yesterday's interest earns interest today. That's why the effective annual yield on a 24% APR card runs closer to 27%.
Does bi-weekly payment really pay off my loan years sooner?
Yes. Twenty-six half-payments per year equal thirteen full monthly payments — one extra payment per year, applied directly to principal. On a thirty-year mortgage that typically shaves four to six years off the term, provided your servicer applies the surplus to principal.
When does debt consolidation actually save money?
When the new APR (including origination fee amortized over the term) is meaningfully lower than the weighted-average APR of the debts replaced, and the new term is not materially longer. A 7% loan replacing 22% credit cards usually wins; a 9% loan stretched to seven years to replace cards you could clear in three usually loses.
Should I pay off debt or invest the extra money instead?
Compare the after-tax return you can reliably earn against the after-tax rate on the debt. A diversified equity portfolio has historically returned about 7% real. Debt above that — most credit cards and personal loans — almost always wins by being paid down first.
Do extra principal payments actually go to principal?
On installment loans you usually have to mark the extra as 'principal only' — otherwise lenders may apply it toward the next scheduled payment, advancing the due date instead of reducing the balance. On credit cards, the CARD Act requires anything above the minimum to go to the highest-APR balance.
Saving instead of borrowing? Our sister site, Compound Interest Calculator, covers the math from the other direction.