How to determine ARV: comping like an appraiser, not an optimist

How do you calculate ARV? After-repair value — what a property will sell for once renovated — is estimated by comping the finished product against recently-sold, genuinely-similar homes nearby, then adjusting for the differences that remain. Every dollar of flip margin, every BRRRR refinance, and every hard-money loan is computed from ARV — which makes it the most consequential number in active real estate, and the one beginners inflate most reliably. The discipline is learnable in an afternoon and refined over a hundred reps: comp like the appraiser who will eventually judge you, because they will.

Key takeaways

ARV = what the RENOVATED house sells for — comped against sold (not listed) properties matching bed/bath, square footage, age, and finished condition.
The comp-selection hierarchy: same subdivision or a few blocks, sold within 90–180 days, within ~20% of square footage, same property type and story count. Every rule you bend costs accuracy.
Use the MEDIAN of your three best comps, not the best sale on the street — comping to the outlier is the single most expensive habit in flipping.
Adjust like an appraiser: bracket the subject (comps above and below), adjust in dollars for concrete differences (garage, bath count, lot), and never adjust more than ~10–15% total.
Every $10k of ARV error flows straight through the 70% rule into your offer — the optimism tax is paid at closing, months later, with interest.

The comp-selection rules

Comping is a filtering exercise, and the filters are ranked. Work down this list and resist every temptation to relax a rule because the result disappoints you:

01Sold, not listedActive and pending listings are asking prices — hopes with photography. Only closed sales are evidence. (Actives ARE useful as your future competition: if three renovated actives sit unsold at your target ARV, the market is voting.)
02Close in distance — and on the same side of every lineSame subdivision or within ~0.5 miles urban/suburban — and never across a school boundary, highway, railroad, or 'that street' locals know. Micro-boundaries move values 10–20% in ways distance radii can't see. Drive your comps; the street tells you what the spreadsheet can't.
03Close in time90 days ideal, 180 acceptable, older only with a documented trend adjustment. Markets move monthly; last summer's comp is a different market's opinion.
04Close in kindWithin ~20% of square footage, same beds/baths bracket, same story count, same type and vintage band. A ranch does not comp a two-story; a 1955 cottage does not comp a 2019 build — appraisers won't cross those lines, so you can't either.
05Matched in condition — to your FINISHED productYou're valuing the renovated house, so comps must be renovated sales at your intended finish level. Comping your mid-grade rehab to the designer flip with the wall of windows is self-deception with a dollar figure.

Adjusting and the median discipline

With 3–5 qualifying comps, adjust for the concrete differences that remain — in dollars, direction always toward the subject: the comp has a garage and yours doesn't, subtract its local value ($8–15k in most markets); the comp lacks your second bath, add ($5–12k); pool, lot size, view, finished basement, each per your market's evidence (an agent or appraiser will calibrate you fast). Two guardrails keep adjustment honest: bracket the subject — at least one comp better and one worse, so the answer is interpolation rather than extrapolation — and cap total adjustments around 10–15% of value; needing more means the comp fails the filters and belongs out of the set. Then take the median of your best three, not the max: the $285k-$292k-$318k comp set supports an ARV near $290k, and the $318k sale is a question to investigate (bigger? corner lot? bidding war?) — never a foundation. Per-square-foot pricing is your cross-check, not your method: $/sqft varies systematically with size (smaller homes run higher $/sqft), so apply it only across genuinely similar sizes.

What a $15k ARV error does to a flip (via the 70% rule)

Through MAO = ARV × 70% − repairs, every ARV dollar moves your maximum offer by 70 cents. Overpay $10.5k on a deal that should net $30k and you've donated a third of the margin before demolition day — the optimism tax, collected at resale, months later.

Sources, and the appraiser's-eye habit

Data: MLS access is the gold standard (one more reason investors get licensed or partner with an investor-friendly agent); public portals' sold data works with care (verify against county records; beware auto-valuations, which price the current condition and know nothing of your renovation); PropStream-class tools speed the filtering. Calibration: walk open houses of renovated inventory in your farm area monthly — comping is pattern recognition, and the patterns live in finished rooms, not photos. The final habit: before every offer, ask "if the appraisal comes in at my number, which three comps did the appraiser use?" If you can't name them, you don't have an ARV — you have a wish. This is doubly binding on BRRRR deals, where the refinance appraisal is the exit, and on novations and wholetails, where a financed retail buyer's appraiser gets the last word on your spread.

Frequently asked questions

+What does ARV mean in real estate?

After-repair value: the price a property will sell for once fully renovated, estimated by comping the finished product against recently-sold, similar, renovated homes nearby. It anchors the flip industry's core formula — maximum offer = ARV × 70% − repair costs — and the loan sizing of most hard-money lenders (65–75% of ARV).

+How many comps do you need for ARV?

Three to five closed sales that genuinely pass the filters: within ~0.5 miles (and the same micro-boundaries), sold inside 90–180 days, within ~20% of square footage, same type and story count, renovated to your intended finish level. Use the median of the best three — a wide search radius full of near-misses is worse than three tight matches.

+Can I use Zillow to determine ARV?

Use portal SOLD data as a starting inventory, verified against county records — but never the automated estimate itself: Zestimates price the house's current state, blend dissimilar sales, and know nothing about your renovation. MLS sold data (via an agent or your own license) remains the standard; the discipline of the filters matters more than the platform.

+What adjustments do appraisers make between comps?

Dollar adjustments for concrete differences — garage, bath count, lot size, pools, finished basements, condition — always adjusting the comp toward the subject, calibrated to local paired-sales evidence. Professional practice brackets the subject (comps above and below) and keeps total adjustments under ~10–15% of value; needing more means the comp doesn't qualify.

+Why do flippers overestimate ARV?

Motivated reasoning with a spreadsheet: comping to the street's best sale instead of the median, borrowing condition from a superior finish level, ignoring micro-boundaries, and stretching the radius until the answer improves. The defense is procedural — fixed filters, median-of-three, name-the-appraiser's-comps — because every $10k of optimism becomes $7k of overpayment through the 70% rule.

Where the number gets used: the 70% rule, flip strategies, and the BRRRR refinance. The other half of the offer math: estimating rehab costs.