What this fix and flip calculator measures
A fix and flip is a short hold. You buy, you repair, and you sell near the after-repair value you typed. The question is not whether the house looks better. The question is whether the sale still covers the purchase, the rehab, the interest, the hold, and the cost of selling. This fix and flip calculator answers that with three headlines: net profit, cash needed, and total-cost ROI.
Net profit is after-repair value minus every cost the engine counts. Cash needed is the investor cash the sources-and-uses view still requires after the loan: purchase, rehab, buying costs, points, interest, and holding, minus the loan proceeds. Total-cost ROI is net profit divided by those costs, not an annualized return. A deal can show a profit and still ask for more cash than you have. Read both numbers before you write the offer.
The free calculator on this page exposes purchase price, rehab budget, and after-repair value because those three numbers move the headlines the most. Everything else starts at the app defaults described in the worked example. That is deliberate. A public page that hid the loan, the hold, and the realtor fee would print a fantasy profit. The defaults are visible in the formula so you can see what was assumed.
Formula
Net profit equals after-repair value minus total costs. Total costs add the purchase price, the rehab budget, holding costs for the months you keep the house, financing costs, buying costs, and selling costs. Holding costs are the monthly stack times the hold: property taxes, insurance, HOA, utilities, and any miscellaneous holding line, spread across the months. The free sample holds for five months.
The default loan basis is purchase plus rehab. The first lien is 90% of that basis. Points are 2% of the loan. Interest is 12% and is charged for the hold, not for a 30-year amortization. Second and miscellaneous liens start at zero. Buying costs on the sample are a $500 title base, $1,500 of miscellaneous buying costs, and $800 of escrow. Selling costs are a 3% realtor fee and a 0.25% transfer fee, both applied to the after-repair value. Staging, warranty, and marketing start at zero.
Total-cost ROI is net profit divided by total costs. It is null when costs are zero. It is not the annualized return on cash, and it is not a letter grade. The paid fix and flip calculator still shows cash to close, committed capital, a max offer against a profit target, and the sensitivity view when rehab or hold time moves. Those controls are behind the subscription because they change the same engine, not because the free page uses a different formula.
Example
Worked example
Illustrative example. The headlines below use the calculator's sample inputs. They are not a flip this company closed.
The worked example uses the app defaults, not a listing. Purchase is $300,000. Rehab is one lump sum of $45,000. After-repair value is $450,000. Hold is 5 months. The loan basis is purchase plus rehab, the first lien is 90% of that basis, points are 2%, and interest is 12% for the hold. Annual taxes are $2,400, insurance is $1,800, and utilities are $250 a month. Buying costs keep a $500 title base, $1,500 of miscellaneous buying costs, and $800 of escrow. Selling uses a 3% realtor fee and a 0.25% transfer fee. On those inputs the fix and flip calculator returns net profit of $62,840, cash needed of $62,035, and total-cost ROI of 16.23%. Change purchase, rehab, or ARV in the free calculator above and those three headlines move. The paid calculator is where hold length, extra liens, and selling costs change.
Read the sample as a check of the formula, not as a house you should buy. If your contractor's number is higher than $45,000, type that higher number. If your agent's after-repair value is lower than $450,000, type the lower number. The headlines will fall. That is the point of a fix and flip calculator: the offer is only as good as the two numbers you are least sure about, rehab and resale.
Contractor assumptions
Rehab is a lump sum you type. The calculator does not break that sum into roof, kitchen, baths, or mechanicals, and it does not look up a cost book. There is no RSMeans feed and no licensed cost database. A number that came from a walkthrough, a contractor's bid, or your own contingency belongs in that one field. If you do not yet have a bid, the lump sum is a guess and the profit is a guess.
RE Underwrite Lab does not bid your house and it is not a scope of work. The app does not visit the property, open walls, or price labor and materials for your zip code. Include contingency inside the lump sum if you want it. The engine will not add a hidden pad.
Hold costs assume the contractor finishes inside the months you set. The free sample uses five months. A late inspection, a permit, or a back-ordered item does not change the formula by itself. You change the hold, in the paid calculator, and interest plus taxes, insurance, and utilities run for the extra months. Utilities on the sample are $250 a month. Taxes and insurance are annual figures spread across the hold.
Common pitfalls
Reading net profit before the rehab lump sum has a roof, a panel, or a permit in it treats a guess as a bid. Put contingency inside that one number. The engine will not add a pad you forgot.
Leaving the hold at the sample length when the schedule is longer understates interest and the monthly tax, insurance, and utility stack. Selling costs are a percent of after-repair value, so a lower resale moves the fee and the profit together.
What stays on the subscription
The "Start the full calculator" button opens an account. A card starts a 48-hour trial. You are not charged during those 48 hours. After the trial, standard is $9.99 a month and founding is $5.99 a month for the first 100 subscribers. The paid fix and flip calculator keeps this formula and adds the rest of the inputs: hold length, three liens, loan basis, buying and selling lines, saved deals, compare, and the branded PDF. The free page cannot save or export.
Nothing on this page is an appraisal, a broker price opinion, or advice to buy. An after-repair value you type is your number. Verify taxes, insurance, lender points, and the contractor's scope before you rely on the headlines.
Questions
What is a fix and flip calculator?
It subtracts purchase, rehab, hold, financing, buying, and selling costs from the after-repair value you enter. This page shows net profit, cash needed, and total-cost ROI from that formula.
Does the free calculator include holding costs?
Yes. The free page keeps the app defaults: five months of hold, taxes, insurance, utilities, a 90% loan on purchase plus rehab, 2 points, and 12% interest. You can change those in the paid calculator.
Why is rehab one number?
The engine is built for a lump-sum budget, not a line-item estimator. Put the contractor's bid, including any contingency you want, in the rehab field.
Is total-cost ROI the same as annual return?
No. Total-cost ROI is net profit divided by total costs. It does not divide by the hold and multiply by twelve. Use it to see how thick the profit is relative to the money the project consumes.
Can I save this deal or download a PDF here?
No. Saving, compare, and the branded PDF are part of the subscription. The "Start the full calculator" button starts that path. The free calculator only shows the three headlines.