How to Calculate ARV From Comps (the Way an Appraiser Would Check It)

After Repair Value is the finished value of the property — what it sells for after your renovation — and it sits at the top of every formula you'll run. Overstate ARV by 5% and everything downstream inherits the error: your MAO is too high, your projected profit is fiction, and the appraisal at exit becomes the moment you find out.

There is no source that hands you ARV. You build it, from comparable sales, and the discipline is in how.

Step 1 — Pull sales, not listings

Comps are closed sales, ideally recent (the fresher the better — many lenders want them inside 6 months, and older comps need justification), because listings are asks and asks are stories. Pull from sources you can defend: MLS solds via an agent, public records, and data platforms like PropStream. Your target set:

• Same immediate area — same subdivision or a tight radius, and never across a boundary the market itself treats as a line (a school zone, a highway, a "wrong side of" street).
• Similar size — commonly within roughly ±20% of your subject's square footage.
• Same bones — bed/bath count, stories, garage, lot type in the same family.
• Renovated condition — you're valuing your finished product, so the comps must be finished-quality sales, not distressed ones.

Three to six genuinely comparable sales beat fifteen loose ones.

Step 2 — Adjust for the differences

No comp matches perfectly, so you adjust the comp's price toward your subject: if the comp has something your subject won't, subtract its value; if your subject will have something the comp lacks, add. Square footage differences get adjusted at a defensible per-square-foot figure for the area (derived from the comps themselves, not a national number); beds, baths, garages, pools, and lot advantages get market-based lump adjustments.

Two rules keep this honest. First, adjust from evidence — the spread between otherwise-similar comps is what tells you what a bathroom or a garage is worth here. Second, watch total adjustments: if you're moving a comp's price more than about 15–20% to make it "comparable," it isn't comparable. Drop it.

Step 3 — Reconcile across multiple sources, not one number

Here's where most quick ARVs fail: they anchor on a single figure — one comp, one agent's opinion, one algorithm. The defensible approach is to compute value several ways and reconcile:

• Adjusted comp average — the core method above.
• Price-per-square-foot — median $/sqft of your renovated comps × subject sqft, as a cross-check.
• Third-party estimates — automated valuations are noisy on individual houses, but as one input among several they flag when your comp-based number is an outlier.

If the methods cluster, you have an ARV. If they disagree widely, the disagreement is the finding — go figure out why before you write an offer. Then, for your MAO, consider using a number below your point estimate; conservatism at the top line protects every line beneath it.

The mistakes that inflate ARV

• Comping to listings. Asks are hopes.
• The hero comp. One outlier sale — the over-improved house, the bidding war — treated as the market.
• Crossing invisible boundaries. The market knows where the lines are even when the radius tool doesn't.
• Ignoring trend. In a moving market, a 9-month-old comp is a different market's price.
• Valuing your renovation at retail-plus. Your finished house sells like the other finished houses — not like the one you fell in love with on Instagram.

Frequently asked questions

What does ARV mean in real estate?

After Repair Value — the market value of a property once your planned renovation is complete, established by comparable finished sales.

How many comps do I need for ARV?

Quality beats quantity: three to six recent, genuinely similar, renovated-condition sales that you've adjusted for differences will outperform a large loose set every time.

What's the ARV formula?

There isn't a single formula — ARV is a reconciliation. The workhorse method is adjusted comparable sales, cross-checked with median price-per-square-foot times your subject's square footage, and sanity-checked against third-party estimates.

Can I use Zillow for ARV?

As one cross-check among several, cautiously. Automated estimates don't know your renovation scope or condition. Never as the primary source for an offer you'll sign.