House Flip Calculator
Project cost, profit, ROI and the 70% rule check for a fix and flip. 100% free, no signup. Everything runs in your browser.
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Give this calculator six inputs: purchase price, rehab budget, how many months you expect to hold, your monthly holding costs, selling costs as a percentage of the sale, and your target sale price. It hands back the numbers that decide whether a flip is worth doing: total project cost, projected profit, return on investment, and a 70 percent rule check showing the maximum offer the classic screen would allow. All of the math runs locally in your browser, and nothing you type goes anywhere.
The 70 percent rule says the most you should pay is 70 percent of the after repair value minus rehab costs. I show it because nearly every flipper uses it as a first filter, and I annotate it because treating it as gospel is how people overpay in cheap markets and never buy anything at all in expensive ones.
How to use
- Enter the purchase price you expect to pay.
- Enter your full rehab budget, including a contingency for the surprises behind the drywall.
- Set the holding period in months and your monthly holding costs: loan interest, utilities, insurance and property taxes.
- Set selling costs as a percentage of the sale price, covering agent commissions and seller-side closing costs.
- Enter your target sale price, which is your after repair value.
- Read the outputs: total project cost, profit, ROI and the 70 percent rule maximum offer.
- Stress test it. Add two months of holding, trim the sale price, and see whether the deal still breathes.
Why use our house flip calculator?
Holding costs get their own inputs because time is where flips die. Every story I have heard about a flip going sideways was really a story about months: the permit that took six weeks, the contractor who vanished, the buyer who fell through. Each extra month is loan interest, taxes, insurance and utilities paid out of profit, and this calculator makes that bleed visible before you commit instead of after.
Selling costs are modeled as a percentage because people anchor on the sale price and forget how much of it they hand back at closing. Commissions and seller-side costs come off the top, and on a thin deal that give-back is the difference between profit and a very educational break-even. Our seller net proceeds calculator itemizes that side in detail when you want more than a percentage.
ROI here is profit over total cash in the project, which keeps you honest when comparing deals of different sizes. A bigger profit number on a much bigger project can be a worse use of your money and your year, and the percentage is what reveals it.
Now the 70 percent rule, honestly. It is a screening heuristic, not a law of nature. In expensive coastal markets it rejects nearly everything, because margins there live in appreciation and speed rather than deep discounts. In cheap markets it can approve deals where the dollar profit is too small to survive one surprise. Use it the way experienced flippers actually do: as a fast first sort, followed by the full arithmetic this calculator does above it.
And your numbers stay yours. Deal analysis is competitive information, and every keystroke here stays in your browser, unstored and unseen.
Who is this tool for?
Kitchen table screening is the core use. A listing catches your eye, you know rough rehab numbers for your market, and two minutes later you know whether to book a viewing or keep scrolling. Flipping rewards the people who can evaluate twenty deals a week, and this makes each evaluation nearly free.
Setting a walk-away number before negotiating is the discipline use. Run the numbers, find the purchase price where the deal stops working, write it down, and let it argue with you when the agent says another buyer is interested. The 70 percent rule line gives you a second reference point for the same decision.
Comparing a flip against keeping the property is worth an honest look, because sometimes the resale market says sell and the rental market says hold. Our BRRRR calculator models the refinance-and-rent route, and the cash on cash return calculator shows what your capital would earn if it stayed in the deal.
Stress testing is the use that saves people. Rerun your deal with two extra holding months and a slightly weaker sale price, and see if it survives. If profit only exists in the best case, you have not found a deal, you have found a bet.
Frequently asked questions
A screening heuristic: pay no more than 70 percent of the after repair value, minus rehab costs. The 30 percent gap is meant to absorb holding costs, selling costs and profit. This calculator shows the maximum offer it implies for your inputs.
As a first filter, yes. As a final answer, no. It is blunt by design: too strict for expensive markets, too loose for cheap ones where thin dollar profits hide behind healthy-looking percentages. Screen with the rule, then decide with the full numbers.
Everything the property costs per month while you own it: loan interest or hard money payments, property taxes, insurance, utilities, and any HOA dues. If financing is part of the picture, our mortgage payment calculator helps pin down the loan portion.
Agent commissions plus the seller-side closing costs, entered as one percentage of the sale price. For a plain-English walkthrough of what buying and selling a home actually costs, the CFPB's owning a home resources are genuinely worth a read.
Projected profit divided by total project cost: purchase, rehab, holding and selling costs combined. It measures how hard every dollar in the project worked, which makes deals of different sizes comparable.
After repair value: what the property should sell for once the rehab is done, based on comparable finished sales nearby. It is the single most dangerous input to get wrong, so build it from real comps, not optimism.
No. Flip profits are often taxed as ordinary income depending on how you operate, and that is a conversation for an accountant, not a web tool. Treat the output as pre-tax.
Yes. The math runs entirely in your browser. Nothing is uploaded, stored or shared, and your deal pipeline stays your business.