The 70 rule calculator is the fastest way to filter out bad flip deals before you waste time on due diligence. Here's how it works — and how to apply it in Palm Beach, Broward, and Miami-Dade.
Every experienced house flipper uses the 70 rule calculator as their first filter. Before you tour a property, before you call a contractor, before you get excited — you run the numbers. The formula takes 30 seconds and tells you whether a deal deserves any more of your time.
What is the 70 rule calculator?
The 70 rule calculator gives you the maximum price you should pay for a property you intend to flip. The formula is simple:
- Maximum Offer = (ARV × 0.70) − Estimated Repair Costs
ARV stands for After Repair Value — what the property will be worth once fully renovated and ready to sell. The 30% cushion covers your profit, holding costs, closing costs, and agent commissions.
70 rule calculator example in South Florida
Let's say you find a dated 3/2 in Delray Beach. Comparable renovated homes on the same street are selling for $420,000 — that's your ARV. A contractor quotes $65,000 for a full renovation. Here's the math:
- ARV: $420,000
- 70% of ARV: $294,000
- Minus repairs: − $65,000
- Maximum offer: $229,000
If the seller is asking $265,000, the deal doesn't work at current renovation costs. You'd need to either negotiate the price, find cheaper rehab solutions, or walk away.
When the 70 rule is a starting point, not a hard ceiling
In highly competitive South Florida submarkets — Coconut Grove, Pinecrest, parts of Boca Raton — you'll rarely find deals that clear the 70% threshold at list price. That doesn't mean flipping is impossible. It means you need to:
- Source off-market through wholesalers, direct mail, or agent relationships
- Find properties where your renovation estimate is significantly lower than competitors' (scope control)
- Use a higher ARV with very tight comps — don't guess, confirm with an agent
Some experienced flippers adjust to an 80% rule in ultra-hot zip codes where holding times are short and rehab scopes are cosmetic. But if you're newer, stick to 70% — it protects you from the surprises that always show up mid-renovation.
How to find the ARV accurately
Your 70 rule calculator is only as good as your ARV. Garbage in, garbage out. Here's how to get it right in South Florida:
- Pull sold comps within a quarter-mile, same bed/bath count, sold in the last 90 days
- Adjust for square footage differences ($80–$120/sf in most South Florida markets)
- Confirm with a local agent — they have MLS access and can spot issues with your comp selection
- Be conservative: use the median comp, not the outlier
Our Fix & Flip / BRRRR Calculator can help you stress-test your deal across different ARV and repair scenarios before you make an offer.
Common mistakes with the 70 rule
Most new flippers who lose money violate the 70 rule in one of two ways. First, they inflate the ARV to make the deal work on paper — using a top-of-market sale from two years ago instead of current comps. Second, they underestimate repairs — using a phone-quote contractor number that balloons once walls open up.
The fix is simple: be ruthlessly conservative on both inputs. A deal that works at conservative estimates will work in reality. A deal that only works if everything goes perfectly almost never does.
Ready to find flip opportunities in South Florida that actually pass the 70 rule? Tell us your criteria and we'll send you off-market deals that pencil out. We source across all six counties — Palm Beach, Broward, Miami-Dade, St. Lucie, Martin, and Highlands. Learn more at Florida Realtors market data.
