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Building Capital / Fix & flipThe first door · Year 3 · Deep dive

The 70% rule in house flipping: how it works, when it lies, and the math behind it

Maximum offer = 70% of ARV minus repairs. Why the formula exists, what's actually inside the missing 30%, and when 70 is the wrong number.

5 min

What is the 70% rule? A screening formula for flips: pay no more than 70% of the after-repair value (ARV) minus repair costs. For a house worth $300,000 fixed up and needing $40,000 of work, the maximum offer is $300,000 × 0.70 − $40,000 = $170,000. The 30% you're not paying isn't profit — it's selling costs, holding costs, financing costs, and your margin, in that order. Understand what lives inside the 30% and you'll also understand when the rule should be 75% — or 65%.

Where the 30% actually goes

The rule looks like a 30% profit until you itemize it on the $300k example:

Inside the 30% — $300k ARV flip bought at the 70% rule
Sale at ARV: $300kSale at ARV$300kPurchase (70% − repairs): $170kPurchase (70% − repairs)$170kRepairs: $40kRepairs$40kSelling costs (~8%): $24kSelling costs (~8%)$24kHolding + financing (6 mo): $21kHolding + financing (6 mo)$21kPre-tax profit: $45kPre-tax profit$45k
Selling costs: agent commissions, closing, concessions. Holding/financing: hard money interest and points, insurance, taxes, utilities across a ~6-month project. Profit ≈ $45k — about 15% of ARV, before income tax.

That ~15% margin is the payment for risk, work, and the months of your life — and it's what evaporates first when the rehab runs over or the market cools mid-project. The rule's discount exists because flips have brutal fixed costs: you pay full transaction costs on both ends of a short hold.

Using the rule correctly

  1. 01Establish ARV from evidenceThree to five sold comps: same neighborhood, same size ±20%, same style, renovated condition, sold in the last 3-6 months. Listings show what didn't sell yet. ARV is the number the flip's buyer's appraiser must reach — respect that.
  2. 02Estimate repairs with a walkthrough, not a guessRoof, HVAC, electrical, plumbing, foundation first — the expensive invisible systems. Then cosmetics by square foot. Before an offer, replace your estimate with a contractor's bid plus 15% contingency.
  3. 03Apply the formula as a filterMAO = ARV × 0.70 − repairs. Above the answer, walk. The rule's power is the speed of the no — analyzing 30 deals to offer on 3 beats falling in love with the first.
  4. 04Then underwrite the survivor line by lineFor any deal you'll actually offer on: real financing quote, month-by-month holding budget, realistic timeline, exit price at conservative comps, and your break-even sale price. The rule found the deal; the spreadsheet buys it.

When 70% is the wrong number

The rule embeds fixed-ish percentages against costs that aren't fixed:

Push toward 65% (more discount)Can work at 75-80% (less discount)
Price bandCheap houses (<$150k ARV) — fixed costs eat a larger shareExpensive houses ($500k+) — margins are dollars, not percentages
MarketSlowing, high days-on-market, price cuts spreadingFast, supply-starved, multiple offers on renovated product
TimelineBig structural projects, permit-heavy citiesCosmetic-only refreshes closing in 60-90 days
FinancingExpensive hard money, points on pointsCash or cheap capital that shrinks carry
Your experienceFirst three flips — pay for your own error barsProven crew, tenth project, known neighborhood

Flipping's place in the long game

A flip converts skill and nerve into a taxed lump of capital — ordinary income rates, no depreciation shelter, no step-up ending. That makes flipping a fine engine and a poor destination: the twenty-year math favors holding. Flip to build the capital pile; then let the BRRRR method and the Cashflow pillar put that pile to work in assets you never have to sell.

Frequently asked questions

+What is the 70% rule in real estate?

A flipper's screening formula: never pay more than 70% of a property's after-repair value minus repair costs. On a $300,000 ARV house needing $40,000 of work, the maximum offer is $170,000. The 30% discount covers selling costs, holding costs, financing, and the flipper's profit margin.

+How do you calculate ARV?

After-repair value comes from 3-5 sold comparables: same area, similar size and style, renovated condition, sold within the last 3-6 months, adjusted for differences. Use sold prices, not listings — ARV must be a number a buyer's appraiser will support, or your exit price is fiction.

+How much profit does the average house flip make?

Industry gross-profit figures often show $60-70k per flip, but gross profit ignores rehab, holding and financing costs. A disciplined flip bought near the 70% rule nets roughly 10-15% of ARV pre-tax — around $30-45k on a $300k property. Thin-margin flips routinely net zero after surprises.

+Is the 70% rule too strict in expensive markets?

Often, yes. On high-priced homes the fixed costs are a smaller percentage, so 75-80% can still leave six-figure dollar margins. Conversely, on sub-$150k houses 70% is frequently too generous. Anchor on dollars of margin after itemized costs, and let the percentage float.

+Is flipping houses still profitable?

Yes, for operators who buy deep enough — which is the actual skill. Higher rates raise holding costs and thin the buyer pool, punishing sloppy underwriting first. The 70% rule (tightened in slow markets) exists precisely to keep you out of break-even projects.