House Flip Estimator
Purchase price, rehab budget, holding costs, selling costs, financing — one model that turns them into profit, ROI, and annualized return, so you know your maximum allowable offer before you make it.
The deal
Max allowable offer
The highest price you can pay and still hit your target — back-solved from your real costs, not the 70% shortcut.
$350,000 ARV − $108,827 costs − $30,000 target profit = $211,188
Hold-period sensitivity
Same deal, different timelines. Holding costs and loan interest keep running every month you own it — time is the silent deal-killer.
| Hold | Profit | Cash-on-cash ROI | Annualized ROI |
|---|---|---|---|
| 45 days | $2,500 | 2.1% | 18.0% |
| 90 days | -$2,000 | -1.6% | -6.3% |
| 180 daysyour hold | -$11,000 | -8.3% | -15.9% |
| 270 days | -$20,000 | -14.1% | -18.3% |
Where the money goes
| Purchase price | $250,000 |
| Rehab | $60,000 |
| Holding costs (excl. interest) | $9,000 |
| Loan interest (interest-only) | $9,000 |
| Buy closing | $5,000 |
| Sell closing | $28,000 |
| Total project cost | $361,000 |
How the math works
Cash invested is every dollar you must put in: down payment, rehab, holding costs, loan interest, and buyer closing costs. Total project cost adds the purchase price itself and the selling costs, because profit is measured against everything the deal consumed: profit = selling price − total project cost.
Financing is modeled interest-only: each month you pay interest on the outstanding loan balance and repay the principal in full at sale. That matches how hard-money and bridge loans used for flips actually work — there is no principal paydown during a 4–8 month hold, so amortizing the loan would understate your interest cost.
ROI is cash-on-cash (profit ÷ cash invested), the number flippers actually compare. Annualized ROI compounds it to a yearly rate — a 20% return in 6 months annualizes to 44%, which is why hold time matters as much as margin. The max-offer solver inverts the math: given your target ROI, it bisects the purchase price to find the most you can pay.
Common questions
Why assume interest-only instead of a normal amortizing loan?+
Flips are almost always financed with hard-money or bridge loans, which are interest-only with a balloon repayment at sale — typically 9–12% annual rates. A 30-year amortizing mortgage would show principal paydown building equity, which doesn't happen on a 6-month hold and would make the deal look better than it is.
What should I include in holding costs?+
Property taxes, insurance, utilities, HOA dues, and lawn/snow maintenance for every month you own the property — plus the loan interest, which the calculator adds separately. The most common beginner mistake is underestimating hold time: budget for the rehab plus 2–3 extra months for listing and closing.
What ROI should I target on a flip?+
The classic 70% rule (pay no more than 70% of ARV minus repairs) implies roughly a 20–30% cash-on-cash return after costs. Use the target-ROI slider to encode your own rule — the max-offer readout then tells you your walk-away price before you fall in love with a property.
Does the profit figure include taxes?+
No — profit here is pre-tax. Flips held under a year are generally taxed as short-term capital gains (or ordinary income if you're deemed a dealer by the IRS). Set aside a portion of the projected profit for taxes and confirm your status with a CPA.