House Flip Analyzer

The number that keeps flippers out of trouble is not the profit. It is the ceiling: the most you can pay for a house and still clear the profit you decided on before you walked in.

So this works backwards. You set the resale value, the works, the costs and the profit you will not go below, and it gives you the price. Offer above it and the tool says so in a sentence, in red, with the amount you are over. That is not a criticism of your judgement, it is the thing you bought it for — walking away is a result.

It starts every growth assumption at zero and never assumes the sale price will drift up while you own it. Instead it shows the other direction: what the profit becomes if the works run twenty per cent over, if it sells for five per cent less, if it takes twice as long to shift, and if all three happen together, which is not unlucky but ordinary. A deal that only survives when everything goes your way is not a deal.

The rest is the arithmetic nobody enjoys doing twice: every cost in one place, the holding cost across the months you actually expect to own it, return on cost, and profit per month so a fast small project can be compared with a slow large one.

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 cannot tell you what a house will sell for or what the works will cost. Those two numbers are yours, they are where flips go wrong, and the stress table exists precisely because they move.

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.