House Flipping Calculator: Profit Formula, the 70% Rule & Real Costs
Quick Answer
- *House flip profit = Sale Price − (Purchase Price + Rehab + Holding Costs + Selling Costs).
- *The 70% rule: pay no more than 70% of ARV minus repair costs. On a $300K ARV home needing $40K in repairs, your max offer is $170,000.
- *Average gross flip profit was $66,000 in 2024 (ATTOM), with a gross ROI of roughly 27%.
- *Holding costs, selling commissions, and rehab overruns are the three biggest profit killers most first-timers miss.
House Flipping by the Numbers
House flipping hit a 10-year high in volume in 2022 before cooling. Here's where the market stands today, according to ATTOM Data Solutions' 2024 U.S. Home Flipping Report:
- 308,922 single-family homes and condos were flipped in 2024 — about 8.7% of all home sales.
- Average gross flip profit: $66,000 per deal.
- Average gross ROI: 27.5% (down from a peak of 51% in 2016 as home prices and rehab costs rose).
- Median days from purchase to resale: 162 days (roughly 5.5 months).
- Flipped homes sold at a median price of $306,000, up from $275,000 in 2022.
Gross ROI sounds attractive. But gross figures exclude financing costs, holding costs, and selling commissions. Net ROI — what you actually keep — typically runs 10–20 percentage points lower. That's why a rigorous cost calculation matters before you put in an offer.
The 70% Rule: Your First Filter on Every Deal
Experienced flippers use the 70% rule as a quick sanity check before digging into detailed numbers. The formula:
Maximum Purchase Price = (ARV × 0.70) − Estimated Repair Costs
Where ARV (After-Repair Value) is the estimated market value of the property after all renovations are complete, based on comparable sales in the same neighborhood.
Worked Example
| Input | Value |
|---|---|
| After-Repair Value (ARV) | $300,000 |
| 70% of ARV | $210,000 |
| Estimated Repair Costs | $40,000 |
| Maximum Offer Price | $170,000 |
If you pay $170,000 for this house and spend $40,000 on repairs, your total cost basis is $210,000. Selling at $300,000 leaves $90,000 gross — which covers your closing costs on the buy side (~$4,250), holding costs for 5 months (~$7,500), and selling costs (~$24,000), leaving roughly $54,000 net profit.
The 30% buffer exists specifically to absorb those transaction and carrying costs. If you pay more than the 70% rule allows, you're eating into that buffer and one surprise (a bad inspection, a slow market, a contractor delay) can wipe out your profit entirely.
5 Signs a Deal Passes the 70% Rule Check
- Strong comparable sales within 0.5 miles support your ARV estimate with at least 3 recent comps.
- Repair scope is clearly defined — cosmetic vs. structural, with contractor bids in hand.
- Your offer price leaves at least 30% headroom after subtracting repairs from ARV.
- The neighborhood has consistent buyer demand (days on market under 30 for comps).
- You have a clear exit strategy if the property doesn't sell — rental cash flow covers your carrying costs.
Full Cost Breakdown: A Real Deal Example
The 70% rule is a filter, not a full analysis. Before you close, model every dollar. Here's a complete cost breakdown for a $170,000 purchase on a home with a $300,000 ARV and $40,000 rehab budget:
| Cost Category | Amount | Notes |
|---|---|---|
| Purchase price | $170,000 | Negotiated offer |
| Buyer closing costs | $4,250 | ~2.5% of purchase price |
| Renovation / rehab | $40,000 | Contractor bids + 15% contingency |
| Holding costs — mortgage (5 mo.) | $5,100 | Hard money at ~10%, interest only |
| Holding costs — insurance (5 mo.) | $625 | Vacant property policy ~$1,500/yr |
| Holding costs — taxes (5 mo.) | $1,250 | Estimated $3,000/yr prorated |
| Holding costs — utilities (5 mo.) | $500 | Power + water during rehab |
| Agent commission (sell side) | $18,000 | 6% of $300,000 sale price |
| Seller closing costs | $6,000 | 2% of $300,000 |
| Total costs | $245,725 | |
| Sale price | $300,000 | |
| Net profit | $54,275 | ~22% ROI on total cost |
A 22% net ROI on a 5-month hold is a solid deal. That's roughly 53% annualized before taxes. But notice how much of the gross margin gets consumed by transaction and holding costs: $35,725 in fees and carrying charges on a $130,000 gross spread.
6 Costs First-Time Flippers Always Underestimate
- Holding costs pile up fast.Five months of mortgage interest, insurance, taxes, and utilities routinely runs $8,000–$15,000. Every week the property sits unsold adds to this number.
- Rehab overruns are the rule, not the exception.Once walls open up, surprises emerge: outdated wiring, subfloor rot, plumbing code violations. Build in a 15–20% contingency buffer on every budget.
- Selling commissions hit 5–6%.On a $300,000 sale, that's $15,000–$18,000 off the top. Some investors use flat-fee MLS services to reduce this, but buyer's agent commissions (2–3%) are still common.
- Permits and inspections.Major renovations require permits in most jurisdictions. Unpermitted work can kill a deal at the buyer's inspection. Budget $1,500–$5,000 depending on scope.
- Hard money loan fees.Most flippers use hard money financing at 8–12% interest plus 1–3 origination points. On a $170,000 loan, 2 points upfront = $3,400 before you even start the rehab.
- Tax treatment.Profits from flips held less than one year are taxed as ordinary income (up to 37% federal), not the preferential 15–20% long-term capital gains rate. Factor this into your net return projection.
How to Estimate ARV Accurately
Your entire deal thesis depends on a reliable ARV. A 10% error on ARV on a $300,000 property = $30,000 swing in projected profit. Here's how to estimate it properly:
Find True Comparable Sales (Comps)
Pull sold listings from the MLS (through an agent) or Zillow/Redfin within the last 90 days, within 0.5 miles, with similar square footage (±20%), same number of bedrooms and bathrooms, and similar lot size and condition. If you can't find 3–5 tight comps, the ARV is uncertain and you need to expand your search or widen your margin.
Adjust for Differences
Appraisers typically adjust $50–$150 per square foot for size differences and $10,000–$25,000 for an extra bedroom or bathroom. A garage adds $15,000–$30,000 in many markets. Your finished renovation quality should match the neighborhood's buyer expectations — over-improving for the area caps your upside.
Get a Second Opinion
Have a local real estate agent or investor-friendly appraiser review your comps before you close. The $300–$500 cost of a pre-purchase opinion can save you from buying a deal that looks good on paper but has a weaker ARV than you assumed.
Financing a House Flip
Most flippers don't use conventional mortgages — the 30-day approval process is too slow for competitive markets. Common financing options:
- Hard money loans: Asset-based lending at 8–12% interest, 1–3 points, 6–12 month terms. Fast close (7–14 days). The go-to for most flippers.
- Private money: Loans from individual investors, often at lower rates than hard money. Requires a track record and relationship-building.
- HELOC or cash-out refinance: If you have home equity, this can fund a flip at much lower rates. Risks your primary residence if the deal goes wrong.
- Cash: The cleanest option — no financing costs, faster close, stronger offers. Requires significant capital reserves.
Whatever financing you use, model the actual monthly cost into your holding cost calculation. A 5-month hold on a $170,000 hard money loan at 10% interest-only costs approximately $7,083 in interest alone.
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Frequently Asked Questions
What is the 70% rule in house flipping?
The 70% rule says you should pay no more than 70% of a property's after-repair value (ARV) minus your estimated repair costs. Formula: Maximum Purchase Price = (ARV × 0.70) − Repair Costs. On a $300,000 ARV home needing $40,000 in repairs, the max offer is $170,000. The rule builds in a profit margin and cushion for unexpected costs.
What is a good profit margin for flipping a house?
Most experienced flippers target a net profit of at least $25,000–$40,000 per deal, or a 10–20% return on total investment. ATTOM Data Solutions reported the average gross flipping profit was $66,000 in 2024, though gross ROI has declined from peaks above 50% to around 27% as home prices and rehab costs have risen.
What costs do house flippers typically underestimate?
First-time flippers most often underestimate holding costs (mortgage, insurance, taxes, utilities for 4–6 months), buyer-side closing costs on purchase (2–3%), selling commissions (5–6%), permit and inspection fees, and renovation overruns. Experienced investors add a 10–20% contingency buffer to every rehab budget.
How long does it take to flip a house?
According to ATTOM's 2024 U.S. Home Flipping Report, the median time from purchase to resale for flipped homes was approximately 162 days — about five and a half months. This includes finding the property, renovating, listing, and closing. Faster flips reduce holding costs and improve annualized ROI significantly.
Do I need a license to flip houses?
You do not need a real estate license to flip houses as an investor. However, flipping more than a few homes per year may trigger dealer status under IRS rules, changing how profits are taxed (ordinary income vs. capital gains). Always consult a CPA familiar with real estate investing before your first deal.
What is ARV in real estate?
ARV stands for After-Repair Value — the estimated market value of a property after all planned renovations are complete. It is determined by analyzing comparable sales (comps) of similar homes in the same area. ARV is the anchor number in the 70% rule and every flip profit calculation.