Is the debt payoff calculator free?
Yes. It is completely free to use, with no signup, no account, and no paywall.
How accurate are the results?
The calculator uses the standard formulas for this kind of math, but real-world results can differ once fees, rounding, rate changes, and provider-specific rules come into play. Treat the output as a planning estimate, not a quote.
Does it stay local?
Yes. The numbers you enter are processed entirely in your browser and never leave your device.
How much sooner would an extra 100 a month clear the debt?
On the defaults, a lot. Going from 300 to 400 a month on 8000 at 18% takes payoff from 35 months to 24 and cuts interest from roughly 2293 to roughly 1584. The savings are disproportionate because at high rates most of an early payment goes to interest, and the extra 100 goes almost entirely against principal.
Can I compare the snowball and avalanche methods?
Not directly, since the tool takes one balance. Run each debt separately to see what it costs alone. Avalanche, which pays the highest rate first, always costs less in total interest, and snowball, which pays the smallest balance first, tends to be easier to stick to.
Does it assume I stop borrowing?
Yes. It amortizes a fixed balance down to zero at a constant payment. Any new spending on the same account invalidates the result, which is the main reason real payoff dates slip past the calculated ones.
Why does my lender's interest figure come out higher?
Because the tool divides the annual rate by 12 and compounds monthly. Most credit cards apply a daily periodic rate to the average daily balance, which compounds faster. Treat the interest shown here as a close floor rather than an exact match.
Is my balance sent to a server?
No. The logarithms run in your browser tab. Nothing about your debt is uploaded, logged, or stored, and the page works with the network off.