Real estate comparable sales are recent closings of similar homes in the same area, and they are the most reliable way to estimate what a property is worth. Appraisers, agents, and homeowners all start with the same basic move: find three or more recent sales that resemble the subject property, adjust each one for the differences, and let the cleanest matches carry the most weight in the final number. Do that well and you have a defensible value. Do it loosely and you get a number that falls apart the moment anyone pushes on it.
What Counts as a Comparable Sale
A usable comp shares the subject property’s basic DNA and sold recently enough to reflect the current market. Fannie Mae’s selling guide frames the search area as the “market area” of the subject property, meaning the geographic region most buyers would consider and where competing homes sit.1Fannie Mae. Comparable Sales In practice that often works out to a one-mile radius in the suburbs, a few blocks in a dense city, and a wider reach in rural areas. The test isn’t the distance on a map but whether the same pool of buyers would consider both homes.
Recency
Fannie Mae expects sales that closed within the last 12 months, though the most recent sale isn’t automatically the best one. A nine-month-old sale that closely matches the subject can be more useful than a one-month-old sale that needs heavy adjustments.1Fannie Mae. Comparable Sales In a market where prices are moving quickly, prioritize sales from the last three to six months. In slower areas with few transactions, older comps may be the only option, and that’s acceptable with an explanation of why they still apply.
Physical Match
Compare single-family homes to single-family homes, not to condos or townhouses, because ownership structure and fees change the math entirely. Within property type, Fannie Mae looks for similar physical and legal characteristics, including site, room count, finished area, style, and condition.1Fannie Mae. Comparable Sales Specifically:
- Square footage within a reasonable range of the subject. A 1,500-square-foot home against a 3,000-square-foot home won’t produce a meaningful result no matter how close they sit.
- The same number of bedrooms and bathrooms, which keeps adjustments small.
- Similar age and construction era. A 1960s ranch against a 2020 build introduces too many variables.
- Similar lot size. Land carries value, and a half-acre lot versus a quarter-acre is hard to adjust away.
- Similar architectural style. Ranch to ranch, colonial to colonial.
The fewer differences, the fewer adjustments, and the more credible the final number.
Surroundings
Two homes with identical floor plans can be worth very different amounts if one backs onto a park and the other faces a busy highway. Appraisers call this external obsolescence: value lost to something outside the property lines that the owner can’t fix. Proximity to commercial zones, power lines, railroad tracks, or environmental hazards all qualify. A comp on a quiet cul-de-sac won’t give you a straight read on a subject property fronting an arterial road without significant adjustment, so match the surroundings when you can.
Where to Pull the Data
The Multiple Listing Service is the primary database for closed-sale data, and it’s generally the most reliable starting point. It records the final closing price, which often differs from the original list price, along with seller concessions, days on market, and property details. Access is restricted to licensed brokers and agents, so if you’re not one, ask an agent to pull a filtered set of recent closings for you.
County records are the next source. Every transfer generates a recorded deed, and in most states those records are publicly searchable through the county recorder or assessor. The recorded sale price on the deed tells you what a real buyer actually paid, which is far more useful than the tax assessor’s valuation. Assessors use their own formulas and schedules, and assessed values typically lag behind the market.
One major caveat: roughly a dozen “non-disclosure” states, including Texas, Alaska, Idaho, Utah, Wyoming, Montana, Kansas, Louisiana, Mississippi, and New Mexico, do not make the sale price part of the public record. In those states, county records won’t show what a neighbor’s home sold for, which makes MLS access or help from an agent close to essential.
Public-facing real estate websites pull from various sources and are convenient for a quick sense of neighborhood activity. Treat their automated estimates as a starting point, not a conclusion. They blend public records with listing data and algorithms, and they routinely miss renovations, deferred maintenance, or unusual features that move value.
Adjusting Comp Prices to Match Your Home
No two homes are identical, so after choosing comps, each sale price gets adjusted to account for how it differs from the subject property. This is where DIY analyses most often go off the rails.
Which Way Adjustments Go
Adjustments always apply to the comparable, never to the subject. If a comp sold for $400,000 but lacks a finished basement that the subject has, you add the market value of the basement to the comp’s price, because that’s what the comp would have sold for if it also had the basement. If the comp has a feature the subject lacks, subtract. Every adjustment moves the comp’s price toward what it would have been if the two homes matched.
Market Reaction, Not Renovation Cost
A homeowner who spent $60,000 on a kitchen does not automatically get $60,000 in added market value. The adjustment should reflect what buyers in that market actually pay for the difference, which is often considerably less than construction cost. Fannie Mae requires adjustments to reflect “the market’s reaction” to property differences, not fixed rules of thumb.2Fannie Mae. Adjustments to Comparable Sales An extra full bathroom might add $5,000 to $15,000 in a typical suburban market. A high-end kitchen remodel might contribute $15,000 to $30,000 in perceived value. Those ranges swing with local market, price tier, and buyer expectations.
Seller Concessions
When a seller pays part of the buyer’s closing costs or throws in other financial incentives, the recorded price overstates what the property was worth on its own. Freddie Mac’s guidance says the adjustment should approximate the market’s reaction to those concessions rather than a mechanical dollar-for-dollar reduction, essentially answering what the home would have sold for without the sweeteners.3Freddie Mac. Considering Financing and Sales Concessions: A Practical Guide for Appraisers If you’re pulling comps yourself, check the MLS record for concessions. A $420,000 sale where the seller paid $12,000 toward closing costs doesn’t carry the same weight as a clean $420,000 sale.
Weighting the Final Number
After adjustments, you’ll have three or more adjusted prices. The final value estimate is not a simple average. The comp that needed the fewest and smallest adjustments gets the most weight, because fewer adjustments mean fewer chances to introduce error. A sale on the same street two weeks ago that needed one small adjustment for a half-bath is a stronger indicator than a sale a mile away five months ago that needed adjustments for size, condition, lot, and concessions. Lean on the cleanest comp.
Sales to Exclude or Treat Carefully
Not every recorded sale belongs in your comp set. Foreclosures and short sales usually involve a seller under financial pressure and close below what the property would fetch in a normal transaction. Standard practice is to leave them out when conventional sales are available. In markets where distressed activity dominates, they can be used with a “conditions of sale” adjustment to reflect the below-market pricing.
Non-arm’s-length transactions are the other category to watch. A parent selling to a child, a landlord to a tenant, or one business partner to another all carry a built-in risk that the price doesn’t reflect market value. These are generally excluded from comp analysis. If you spot a suspiciously low sale on your block, check whether it was a family transfer before letting it drag your estimate down.
Your Own Analysis vs. a Lender’s Appraisal
A homeowner’s comp analysis is useful for pricing a listing, evaluating an offer, or contesting a tax assessment, but it won’t satisfy a lender. Lenders rely on a licensed appraisal performed by a state-certified or state-licensed appraiser under uniform standards, and that report is what the lending decision runs on.4eCFR. 12 CFR Part 323 – Appraisals An informal comparative market analysis prepared by an agent, or by you, is a planning tool, not a substitute for the lender’s appraisal.
Using Comps to Push Back on a Low Appraisal
A low appraisal can wreck a transaction. If the appraised value lands below the purchase price, the lender won’t finance the full amount, and the buyer has to cover the gap, renegotiate, or walk. This is where your own comp research pays off, because you can use it to request a reconsideration of value (ROV).
Federal regulators have issued interagency guidance requiring lenders to maintain a process for handling ROV requests from borrowers.5Federal Register. Interagency Guidance on Reconsiderations of Value of Residential Real Estate Valuations Fannie Mae requires lenders to accept borrower-initiated ROV requests and to provide a disclosure explaining the process when they deliver the appraisal report.6Fannie Mae. Appraisal Quality Matters
An effective ROV submission needs:
- Specific deficiencies in the appraisal. Point to the particular comp that looks off or the adjustment that doesn’t reflect the market. Vague complaints don’t move the needle.
- Alternative comparable sales. You can submit up to five, with supporting data and MLS listing numbers, that the appraiser didn’t consider and that more closely match the subject.
- Property facts the appraiser missed, such as a recent renovation, an incorrect square footage, or an overlooked feature, with documentation.
The lender reviews the request and, if warranted, sends it to the original appraiser for reconsideration. Only one borrower-initiated ROV is allowed per appraisal.6Fannie Mae. Appraisal Quality Matters The appraiser doesn’t have to change the value, but strong overlooked comps give the number a real chance of moving. That is the moment your comp work earns its keep.