Eight flips in and still winging the underwriting? You're not alone. Most flippers — even experienced ones — rely on a mix of gut feel, spreadsheets, and hard-won contractor relationships to ballpark ARV and rehab costs. The process works, until it doesn't. And when it misses, it tends to miss expensive.
Here's how to build a more systematic approach to estimating after-repair value (ARV) and rehab costs so you stop leaving money on the table — and stop chasing deals that were never going to pencil.
How to Estimate ARV the Right Way
ARV is what a fully renovated version of the property will sell for in today's market. It's not what the neighbors are listed at. It's not what Zillow says. It's what similar homes in comparable condition have actually sold for in the last 90 days.
Step 1: Find true comps. Pull sold listings within 0.5 miles and 90 days. Filter for similar square footage (±200 sqft), bed/bath count, and condition. If you're in a dense market, you'll have plenty. If you're in a rural or suburban market, you may need to stretch to 6 months or 1 mile — just flag that as a higher uncertainty.
Step 2: Adjust for condition delta. The comps you're pulling are for finished homes. Mentally price the gap between your target and those comps. A dated kitchen and original bathrooms might be a $25–40k discount in a $300k market. A full gut job could be $60–80k. Your job is to figure out what "finished" means in that neighborhood.
Step 3: Sanity-check your price per square foot. Divide your ARV estimate by the square footage. Does it match the $/sqft of your comps? If you're estimating $250/sqft in a neighborhood where comps close at $190/sqft, you're wishful thinking.
Step 4: Use tools to cross-reference, not replace. Automated valuation tools — whether it's an AVM from your MLS, a paid data platform, or an AI-powered tool — are useful as a second opinion. They're fastest for quick screening. But always ground-truth against real sold data before you commit.
How to Estimate Rehab Costs Without a Contractor Walk
Getting a contractor to the property on every early screening deal is expensive in time. Here's how to build a reliable first-pass estimate:
Build a cost-per-item reference list. After every project, log what you actually paid for each scope item: roof replacement, HVAC, kitchen gut, bathroom remodel, flooring, exterior paint, etc. After 8 flips you should have enough data to run a rough estimate on a new property in 20 minutes.
Use a scope-first, price-second approach. Walk (or do a drive-by + listing photos) and build a scope list before you think about numbers. What needs to be done? Full kitchen? One bath cosmetic, one bath gut? Roof or roof life remaining? HVAC condition? Foundation concerns? Once the scope is locked, apply your unit costs.
Budget with a cushion tier. A simple mental model:
- Cosmetic (paint, flooring, fixtures): $15–25/sqft
- Medium rehab (kitchen + bath updates, some systems): $30–50/sqft
- Full gut or distressed (everything open, mold/structural): $60–100+/sqft
These are rough nationwide ranges. Calibrate them to your market and your contractors.
Flag unknowns explicitly. Every estimate should have an "unknown" line item — foundation, roof, HVAC age unknown. Don't ignore the unknowns. Budget for them separately as a risk buffer, typically 10–15% of total rehab.
When to Go Deeper vs. Walk Away
The goal at the early screening stage isn't a perfect number — it's a "worth pursuing or not" decision. Use a simple 70% rule as your filter: your maximum offer should be ≤70% of ARV minus rehab costs. If the numbers don't get close to working at that threshold, don't fall in love with the deal.
Go deeper — contractor walk, title check, full comp analysis — only when the deal pencils at a conservative estimate. Your time is a limited resource. Spend it on deals that have a real path to the return you need.
Key Takeaways
- ARV comes from sold comps, not listings or Zillow. Pull within 90 days, 0.5 miles, same condition profile.
- Build a personal cost-per-item database from your own projects — it's your best rehab estimator.
- Use automated tools for first-pass screening, but always verify against real data before committing.
- Budget for unknowns explicitly — 10–15% risk buffer is not a sign of weak underwriting, it's honest underwriting.
- The 70% rule is a filter, not a formula. Use it to decide whether to spend more time, not to lock in an offer.
Want to run the numbers on a property like this? Frontflip makes it a 10-second question — pull any address, get ARV, flip projections, and comp data in one place.