Debt Payoff Simulator

Snowball or avalanche is an argument people have in the abstract. On your actual balances it has an answer, and it is usually smaller than either side claims.

This runs both, month by month, on the debts you enter: the interest each order costs, the month every debt clears in each, and the difference between them in money and in time. Sometimes the gap is hundreds and the order clearly matters. Sometimes it is eighty pounds, and then the honest answer is to take the snowball, because clearing a whole debt early is worth more than eighty pounds and a plan you stick to beats a better plan you abandon. The tool says which case you are in rather than selling you a method.

The table underneath is the one worth having. It runs your debts at nothing extra a month, then fifty, a hundred, two hundred, three, five hundred, and shows the payoff date and the interest for each. Seeing four years and seven thousand pounds of interest turn into two years and three thousand does more than any advice.

It starts every growth assumption at zero and does one more thing most calculators will not. If your minimum payments do not cover the interest, the balance grows and no number of months clears it. Rather than print a number, it says so, tells you roughly what the interest is costing each month, and lets you find the extra payment that flips it.

Save as many as you like and put any two side by side, figure against figure, with the better one on each line marked and the difference in its own column. That screen is the one that decides things, and it is the part a free calculator cannot do at all.

It does not know your card’s real minimum-payment rule, and most cards use a percentage that falls as the balance does, which makes paying minimums worse than shown here, never better. It is not debt advice. If you are struggling, a free debt charity will do more for you than any calculator.

One HTML file. No account, no subscription, no internet needed. Opens on Windows, Mac and Android; the readme explains the extra step on iPhone and iPad, where Apple blocks JavaScript in downloaded files and every tool of this kind is affected.

Everything lives in your browser on your device. Nothing is uploaded, which is why it works offline and why nobody else can see your figures — and it also means clearing your browsing data deletes it. The tool does not pretend otherwise: the header shows how long since your last export at all times, turns amber after three days and red after seven, and export is one click that produces a plain file you keep.