Fix & Flip Strategy

Fix and Flip Profit: How to Run the Numbers First

The house looks like a steal. Peeling paint, outdated kitchen, a bathroom untouched since 1987. But here's what separates investors who make money flipping from those who break even — or worse: the ones who make money run the numbers before they fall in love with the property.

11 min read Updated June 2025 Informational only — not financial or investment advice
Table of Contents
  1. The Fix and Flip Profit Formula
  2. Step 1: Establish the After Repair Value (ARV)
  3. Step 2: Calculate Rehab Costs Honestly
  4. Step 3: Add Holding Costs
  5. Step 4: Calculate Financing Costs
  6. Step 5: Estimate Selling Costs
  7. Full Profit Calculation
  8. The 70% Rule: A Fast First Filter
  9. Fix & Flip Calculator — Free Tool
  10. Where Flippers Lose Money
  11. FAQ

The Fix and Flip Profit Formula

At its core, flipping profit is straightforward. The challenge is filling every variable with a real number — not a hopeful estimate, not a round figure, not whatever the wholesaler told you.

Fix & Flip Profit Formula
Profit = ARV − (Purchase + Rehab + Holding + Financing + Selling Costs)
Your margin for error is smaller than most new investors expect. Optimistic assumptions compound quickly into losses. Work through each component methodically — every variable below needs a real number.

Step 1: Establish the After Repair Value (ARV)

ARV is what the property will sell for once renovation is complete. It's the foundation of every other number in your analysis — if ARV is wrong, everything downstream is wrong.

ARV is not what you hope the property sells for. It's not the Zestimate. It's what comparable renovated properties in the same neighborhood have actually sold for in the last 90–180 days.

How to Find a Reliable ARV

Pull sold comps — not active listings — within a half-mile radius. Match on square footage (within 15–20%), bedroom/bath count, construction type, finish level, and school district. You're comparing to renovated properties, not distressed ones.

📐 Finding ARV — Example Comp Set 3-bed ranch, same neighborhood
Comp
Sale Price
Days Ago
123 Elm St (renovated)
$315,000
42 days
88 Oak Ave (renovated)
$298,000
67 days
14 Maple Dr (renovated)
$307,000
89 days
Conservative ARV
$300,000
Use the low end — not the high

⚠️ Always use the low end of your comp range for ARV. A 5% ARV error on a $300,000 deal is $15,000 — enough to erase your entire profit margin. Work with a local agent or appraiser for a defensible number before committing to a hard money loan.

Step 2: Calculate Rehab Costs Honestly

Rehab cost estimation is where most new flippers bleed money — and where experienced flippers build their edge. Accurate scoping is a skill that saves tens of thousands of dollars per deal.

Walk the property with a detailed checklist. Break renovation into systems and rooms before you estimate anything.

🏗️
Structural & Systems
  • Foundation issues (most expensive surprises)
  • Roof condition and remaining life
  • Electrical panel age and capacity
  • Plumbing type (galvanized = budget replacement)
  • HVAC age and condition
🛋️
Interior
  • Kitchen — cosmetic refresh vs. full gut
  • Bathrooms — fixture swap vs. full tile-out
  • Flooring — refinish hardwood vs. full replacement
  • Paint throughout
  • Doors, trim, hardware
🏠
Exterior
  • Siding condition
  • Windows (single-pane often appraises poorly)
  • Landscaping and curb appeal
  • Driveway, fence, garage
⚠️
Always Add Contingency
  • Add 10–15% on top of your total estimate
  • Opening walls in a 1960s house is an archaeological expedition
  • Mold, knob-and-tube wiring, cracked slabs
  • The unknown always shows up
Rehab Item Typical US Range
Full kitchen renovation$15,000 – $45,000
Bathroom renovation$8,000 – $20,000
New roof (1,500 sq ft)$8,000 – $18,000
HVAC replacement$6,000 – $12,000
New flooring (per sq ft)$4 – $12 / sq ft
Interior paint (full house)$3,000 – $7,000
Electrical panel upgrade$2,500 – $6,000

Example rehab budget for this deal: Kitchen $22k · 2 bathrooms $18k · Flooring $9.5k · Roof $11k · Paint $5k · Exterior/landscaping $4.5k · Contingency 12% ($8.4k) = Total: $78,400

Related: How to Build a Rehab Budget That Doesn't Blow Up Mid-Project →

Step 3: Add Holding Costs

Every day you own the property costs money. Holding costs are the silent profit killer on flips that run long — and renovations almost always run longer than planned. A light cosmetic flip might close in 90 days total. A full gut with structural work could take 6–9 months.

3 mo
Cosmetic flip
~$4,600
5 mo
Mid-level reno
~$17,900
6 mo
Full reno
~$21,500
9 mo
Overrun scenario
~$32,200

The 5-month total above ($17,900) includes financing costs at 11% on a $160,000 loan. The non-financing portion — taxes, insurance, utilities — adds $675/month. It's the loan interest that dominates, which is why every extra month of hold time is so expensive.

Step 4: Calculate Financing Costs

Unless you're paying cash, your capital has a real cost. Hard money loans — the most common flip financing tool — typically carry 9–13% interest annually plus 1–3 upfront points.

On a $160,000 loan at 11% for 5 months:

Cash buyers skip this line — but their opportunity cost of capital still exists, even if it doesn't show up as a payment. Running the numbers honestly means acknowledging the cost of your capital regardless of source.

Step 5: Estimate Selling Costs

Selling costs are non-negotiable and frequently underestimated. On a $300,000 sale at 6% commission + 1.5% seller closing costs:

Staging consistently boosts sale price and cuts days on market. Budget for it — the $2,500 typically pays back multiples.

Putting It All Together: The Full Profit Calculation

Now you have every number. Here's whether this deal works — laid out from ARV down to net profit.

📊 Full Profit Calculation — $300,000 ARV Deal
Example
After Repair Value (ARV)
100%
$300,000
Purchase Price
51.7%
−$155,000
Rehab Costs
26.1%
−$78,400
Holding Costs (5 mo)
1.1%
−$3,375
Financing Costs
3.5%
−$10,533
Selling Costs
8.3%
−$25,000
Net Profit
9.2%
$27,692

⚠️ $27,692 is close but thin. Most experienced flippers target a minimum of 10–15% of ARV as net profit — that's $30,000–$45,000 on a $300,000 deal. At this purchase price, the deal is marginal. One bad subcontractor invoice or a 30-day market delay erodes the margin further. The smart move: negotiate the purchase price down by $10,000–$15,000 before proceeding.

The 70% Rule: A Fast Filter Before You Run Full Numbers

Before investing time in a detailed analysis, the 70% rule gives you a quick sanity check on any potential flip.

The 70% Rule
Max Purchase Price = (ARV × 70%) − Estimated Rehab Costs
Using the example above:
($300,000 × 0.70) − $78,400 = $131,600 maximum offer

The deal above was purchased at $155,000 — $23,400 above the 70% rule maximum. That's precisely why the margin is thin at 9.2% of ARV instead of the target 10–15%.
⚖️
The 70% rule isn't a hard ceiling — but if you're significantly above it, the deal needs a compelling reason to proceed. Some investors use 65% in slower markets. Some stretch to 75% in fast-moving markets with high ARV confidence. Know when to bend it. Never use it as your only analysis.

Related: The 70% Rule in Real Estate: When to Use It and When to Ignore It →

🏚️
Fix & Flip Profit Calculator
Free · Instant · No sign-up
Full tool →

Where Flippers Lose Money: The Most Expensive Mistakes

These four mistakes account for the majority of flips that underperform or generate outright losses. Every experienced flipper has been hit by at least one of them.

📈
Overestimating ARV
The market doesn't care what you need the house to sell for. Comps are facts; projections are opinions. When they conflict, trust the comps. A 5% ARV error on a $300,000 deal is $15,000 — often enough to eliminate your entire profit margin.
🔧
Underestimating Rehab Scope
First-time flippers budget for what they can see. Experienced flippers budget for what they can't — and they've learned that lesson the expensive way. Mold behind drywall, knob-and-tube wiring inside walls that looked fine, slab cracks invisible from the surface. The contingency line exists for a reason.
⏱️
Ignoring Holding Time
A renovation that runs three months over schedule doesn't just cost time. At $1,467/month in hard money interest, it adds $4,400 in financing alone — before the additional taxes, insurance, and utilities stack on top. Every month over your projection is a direct hit to net profit.
🎲
Skipping the Contingency
There is no such thing as a renovation that goes exactly to plan. Budget 10–15% above your cost estimate for unknowns. Investors who skip the contingency line are essentially betting their profit margin that nothing unexpected will happen. That bet loses consistently.

Related: How to Calculate Cash Flow on a Rental Property Before You Make an Offer →

FAQ: Fix and Flip Profit Questions

What is a good profit margin on a fix and flip?
Most experienced flippers target a minimum net profit of 10–15% of ARV. On a $300,000 ARV property, that's $30,000–$45,000. Deals with thinner margins exist but leave little room for cost overruns or market softness — and renovation projects reliably encounter both.
How accurate does my ARV need to be?
As accurate as possible — it's the most consequential number in your entire analysis. A 5% ARV error on a $300,000 deal is $15,000, which can erase your entire profit margin. Use sold comps from the last 90 days, not active listings, and lean conservative. The upside of being right is a good return. The downside of being wrong is a loss.
Should I use hard money or private money to flip houses?
Both are common. Hard money lenders are faster and more accessible but charge higher rates (9–13%) and points (1–3%). Private money from individuals can be cheaper but requires an existing relationship. Either way, factor every financing cost into your profit calculation before you commit. The interest clock starts ticking at purchase.
What's the biggest hidden cost first-time flippers miss?
Holding costs — specifically the compounding effect of a project that runs long. Most new flippers budget rehab costs carefully but underestimate what every extra month of ownership costs when you combine hard money interest, taxes, insurance, and utilities. On a $160,000 loan at 11%, each extra month is ~$1,467 in interest before you add the rest.
How do I know what price to offer on a flip?
Work backwards from ARV. Establish your target profit, add up all costs (rehab + holding + financing + selling), and subtract the total from ARV to arrive at your maximum allowable offer. This is also what the 70% rule approximates. Never let enthusiasm for a property push your offer above what the numbers support — the math doesn't care about your feelings about the property.
Free — no account required

The Renovation Is Where the Work Happens. The Profit Is Where the Math Happens.

Do the math first. Input ARV, purchase price, rehab estimate, loan terms, and hold period — and know your net profit, ROI, annualized return, and maximum allowable offer before you sit across from any seller.

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