How to Pull Real Estate Sales Comps for a Flip

How to pull real estate sales comps for a flip

To pull reliable real estate sales comps for a flip, gather 3–6 recently sold properties within about half a mile of your subject, sold in the last 90 days, that match its bed/bath count, square footage (within roughly 20%), and condition — then adjust each comp's sale price up or down for the differences before landing on your after-repair value (ARV). Everything downstream — your offer, your rehab budget, your profit — rests on getting this number right.

Comps are the single most important input in any deal analysis. A rehab estimate that's off by $10,000 stings. An ARV that's off by $30,000 can turn a projected profit into a loss. Below is the exact process an experienced investor uses to build a defensible comp set.

What actually counts as a comparable sale

A comp is a sold property that a rational buyer would view as a reasonable substitute for your subject. That last word matters: active listings and pending sales tell you what sellers hope to get, not what buyers actually paid. Use closed sales as your foundation.

Strong comps share these traits with your subject:

• Recency — sold within the last 90 days in a normal market; tighten to 30–60 days if prices are moving fast.
• Proximity — ideally within 0.5 miles in a suburban grid; stay on the same side of major dividing lines (highways, school boundaries, railroad tracks).
• Similar size — within roughly 20% of the subject's finished square footage.
• Same bed/bath count — a 3/2 and a 2/1 are not interchangeable.
• Same property type and story count — don't comp a single-story ranch against a two-story colonial.
• Comparable condition — a renovated sale supports your ARV; a distressed sale supports your purchase price.

Step-by-step: building your comp set

1. Define the subject precisely

Write down the subject's beds, baths, above-grade square footage, lot size, year built, garage, and the condition you'll bring it to after rehab. For a flip, you're solving for the finished value, so compare your projected end product against other finished, sold homes.

2. Cast a tight net first

Start with the strictest filters: 0.5 miles, 90 days, same bed/bath, ±20% square footage. If you get 4–6 clean sales, you're done gathering. Only loosen criteria — a wider radius, a longer time window — when you're short on data, and note every compromise you make.

3. Throw out the outliers

Discard sales that don't reflect an arm's-length transaction:

• Sales between family members or businesses.
• Foreclosure and REO sales when valuing a renovated home.
• Homes with obvious atypical features (a massive addition, a tear-down lot).

A good rule of thumb: if a comp's price-per-square-foot is wildly above or below the cluster, investigate before you trust it.

4. Adjust for the differences

No two homes are identical, so you adjust each comp's sale price toward your subject. If a comp has a feature your subject lacks, subtract value from the comp; if your subject is superior, add value. Typical adjustments:

• Square footage — apply a reasonable $/sqft for finish-out differences, not the full market $/sqft.
• Extra bedroom or bath — a defensible dollar figure based on your local market's spreads.
• Garage, finished basement, updated kitchen, lot size, view.

The goal isn't false precision. It's an honest, supportable estimate a lender's appraiser would recognize.

5. Reconcile to a single number

Weight your best comps — closest in location, time, and condition — most heavily. Land on an ARV, then pressure-test it: would the property appraise at that number for your end buyer's financing? If your ARV sits at the very top of the comp range, be conservative and pull it back.

Turning comps into an offer

Once you have a defensible ARV, back into your maximum purchase price. Many flippers use a version of the 70% rule:

Max offer ≈ (ARV × 70%) − rehab costs

On a $300,000 ARV with a $45,000 rehab, that's ($300,000 × 0.70) − $45,000 = $165,000. The 30% haircut absorbs holding costs, closing costs, financing, selling commissions, and your profit margin. Adjust the percentage for your market and deal size — thinner in hot, low-inventory areas; wider where sales are slow. Get your rehab number tight first, because ARV and rehab together drive the whole calculation.

Comps matter for rentals too, but there you're often solving for rent comps and refinance value rather than resale — critical if you're running the BRRRR method to recycle your capital.

Common comp mistakes that cost real money

• Using list prices instead of sold prices. Aspirations aren't data.
• Reaching too far for radius or time just to justify a number you already want.
• Ignoring condition. Comping a gut-renovated sale against your dated subject inflates both ARV and your offer.
• Crossing invisible boundaries. School districts, HOA lines, and busy roads can move value 15–20% within a few blocks.
• Cherry-picking the high comps and discarding the ones that hurt your thesis. Let the data lead.
• Forgetting the market is moving. In a declining market, a 90-day-old comp may already be stale.

Where to get the sales data

Agents pull comps directly from the MLS, which offers the cleanest sold data and full property detail. Investors without MLS access can use county records, appraisal district data, and reputable data aggregators — just verify condition and confirm each sale actually closed.

Manually assembling and adjusting comps is slow, and static spreadsheets don't refresh when the market shifts. Analysis platforms like PropertyWiz AI pull recent sales comps and automate the ARV calculations & adjustments based on appraisal golden standard methodologies - which let you fold comps directly into your deal model, so your ARV, offer price, and projected returns move together instead of living in disconnected files. If you're comparing your workflow options, this breakdown of investment software versus calculators is a useful next read.

Good comps aren't about finding the number you want. They're about finding the number a buyer, an appraiser, and the market will actually support — and then building your deal safely underneath it.