Fix and Flip Calculator Guide
A fix-and-flip calculator is the tool that turns property data into a go/no-go decision. It takes your ARV, purchase price, repair estimate, and cost assumptions and outputs your projected profit, return on investment, and risk margin. This guide walks through every input in a flip calculator and shows you how to use it to evaluate deals quickly and accurately.
The five inputs every flip calculator needs
1. After-Repair Value (ARV)
The estimated sale price after renovation. Calculated from comparable sales of renovated properties in the same area. This is the most important number in your analysis and the one most likely to be wrong. Be conservative. See our ARV guide.
2. Purchase price
What you will pay for the property. Use the 70% rule as your maximum: ARV × 0.70 − repairs. Never exceed this without a compelling, data-backed reason.
3. Repair costs
The total cost of renovation including materials, labor, permits, and a 15% contingency. Walk the property and estimate per room/system. See our repair estimation guide.
4. Holding costs
Monthly costs incurred while you own the property: mortgage payment (if financed), property taxes, insurance, utilities, and HOA fees. Multiply by expected hold time (typically 4-8 months for rehab + sale).
| Holding Cost | Monthly Estimate |
|---|---|
| Hard money interest (12% on $150K) | $1,500 |
| Property taxes | $250 |
| Insurance | $125 |
| Utilities | $150 |
| Total monthly | $2,025 |
At $2,025/month over 5 months: $10,125 in holding costs.
5. Selling costs
The costs incurred when you sell the renovated property:
- Agent commissions: 5-6% of sale price
- Buyer closing cost contributions: 1-3% of sale price
- Title insurance and transfer taxes: 0.5-1%
- Staging and photography: $2,000-$4,000
Total selling costs typically run 8-10% of the sale price.
The complete flip pro forma
Example deal:
ARV: $250,000
Purchase price: $135,000
Repair costs: $42,000
Closing costs (buy): $3,500
Holding costs (5 months): $10,125
Selling costs (9%): $22,500
Total cost: $213,125
Net profit: $36,875 (17.3% ROI)
Key ratios to check
Return on investment: Profit ÷ Total cost. Target 15%+ for a good flip. Below 12% and the risk may not justify the effort.
Profit margin: Profit ÷ ARV. Target 12%+ of ARV as net profit.
All-in to ARV ratio: Total cost ÷ ARV. Should be below 85%. Above 90% means almost no margin for error.
Sensitivity analysis
Run three scenarios for every deal: best case, expected case, and worst case. Vary the ARV by +/- 5% and repairs by +/- 15%. If the deal still profits in the worst case, it is a strong deal. If it only works in the best case, pass.
| Scenario | ARV | Repairs | Profit |
|---|---|---|---|
| Best case | $262,500 | $35,700 | $58,675 |
| Expected | $250,000 | $42,000 | $36,875 |
| Worst case | $237,500 | $48,300 | $14,075 |
In the worst case, you still make $14,075. This deal has enough margin to absorb negative surprises and still profit.
Related articles
- How to Flip Houses: Step-by-Step
- Fix and Flip: The Complete Guide
- How to Calculate ARV
- The 70% Rule Explained
- How to Estimate Repair Costs