How Many Comps Do You Need? What 5% of Every US Appraisal Shows
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Short answer
Three is the regulatory floor, five is what appraisers actually use, and three to six is the working range for a CMA. Fannie Mae requires a minimum of three closed comparables. In FHFA's 5% national sample of 2013–2021 appraisals, the average and median were both five — but the share using five or more fell from 76% in 2013 to 59% in 2021. Beyond about six, extra comps usually mean a looser screen, which widens the range instead of narrowing it.
Most answers to this question are someone's habit stated as a rule. There is actual data, and it is unusually good data — a 5% nationally representative random sample of US appraisals from 2013 to 2021, published by FHFA from the Uniform Appraisal Dataset.
What appraisers actually do
| Number of comps | Share of appraisals |
|---|---|
| Exactly 3 | ~13% |
| 4 | ~19% |
| 5 | ~28% |
| 6 | ~29% |
| 7 or more | ~10% |
Average and median: five. About two-thirds used five or more. Only about one appraisal in eight used the bare minimum of three.
So if you have been told "three comps is standard," that is the floor, not the norm. The norm is five or six.
The minimum, and where it comes from
Fannie Mae's Selling Guide is explicit: "A minimum of three closed comparables must be reported in the sales comparison approach."
Three is therefore the number below which a conventional appraisal is not acceptable for sale to Fannie Mae. It is a compliance threshold, not a target. An appraiser using three is either working in a genuinely thin market or has three unusually good matches.
Note the word closed. Listings and pending sales can be included as supporting data, but they do not count toward the three.
The trend, which is the interesting part
The share of appraisals using five or more comps fell from 76% in 2013 to 59% in 2021 — a 17-percentage-point drop in eight years.
Something changed, and the published analysis documents the trend without settling why. The plausible readings: inventory tightened through the period, leaving fewer recent similar sales to choose from, and appraisal workflow and technology changed how comps are selected. Both are interpretations, not findings.
Either way, the practical takeaway holds. If your comp set is smaller than it would have been a decade ago, you are in the same position as most of the profession, and the response is to be more careful with each comp rather than to hunt for numbers seven and eight.
Where you are changes the answer
Two dimensions in the data, both large.
By state, the share of appraisals with five or more comps ranged from 34% in Mississippi to 90% in California. That is not a difference in professional standards; it is a difference in how much comparable transaction data exists.
By density, the share was about 13 percentage points lower in rural areas than in high-density urban ones — under 61% rural against roughly 75% high-density urban.
A three-comp appraisal in rural Mississippi and a three-comp appraisal in suburban San Diego mean very different things. The first is normal. The second suggests the appraiser did not look hard.
Why more isn't better past a point
Comps are not samples drawn from a population. They are individually selected pieces of evidence, and the selection is the analysis.
When someone adds a seventh and eighth comparable, they almost never found two more excellent matches sitting unused. They loosened a criterion — extended the radius, stretched the date window, widened the size band — and the new comps are by construction worse than the first six.
The effect is measurable in the output: the indicated range gets wider, not narrower. A wider range is easier for a seller, a buyer or an opposing party to argue with, which is the opposite of what the extra work was for.
Four comps within a 6% spread is a price. Nine comps within a 22% spread is a conversation.
The working answer, by situation
| Situation | Target | Why |
|---|---|---|
| Tract subdivision, active market | 4–6 solds | Plenty available; tight screen costs nothing |
| Established mixed neighbourhood | 4–6 solds | Variation needs more evidence to average out |
| Rural or acreage | 3–4, widen time first | The data may simply not exist |
| Custom or unique property | 3, plus cost approach | Sales comparison alone is not enough |
| New construction | 3 settled + pendings in project | Fannie Mae permits pendings to substitute in part |
| Condo in a large building | 3–4, same project preferred | Same-project sales beat nearby ones |
A CMA is not an appraisal, and needs more than solds
Everything above concerns closed comparable sales in an appraisal. A CMA is doing a different job — helping someone decide a list price — and needs three or four categories, not one.
- 3–6 solds establish value.
- Actives show what a buyer can choose instead, right now.
- Pendings are the freshest signal, reflecting agreements weeks old rather than months.
- Expireds show where the market refused to go — often the most persuasive exhibit with an optimistic seller.
See what a strong CMA includes for how these fit together.
The test that beats any count
Take your best comp out of the set. Does the conclusion move materially?
If dropping one comp moves your price by 5% or more, you do not have a supported number — you have one comp and some company. Either find better evidence or widen your stated range to reflect what you actually know.
The bottom line
Three is the lending minimum. Five is the national median and average. Three to six is the practical working range, and beyond six you are usually documenting a loose screen rather than building a stronger case.
Adjust for where you are — the difference between Mississippi and California in this data is 56 percentage points, and it is about data availability, not diligence. Then run the drop-one test, because it tells you more about your confidence than any count.
Frequently asked questions
How many comps are required in an appraisal?
Fannie Mae's Selling Guide requires a minimum of three closed comparable sales in the sales comparison approach. Most appraisals use more: in FHFA's nationally representative sample of appraisals from 2013 to 2021, the average and median were both five.
Is 3 comps enough?
It meets the lending minimum and about 13% of appraisals in the FHFA sample used exactly three. It is enough when all three are genuinely close matches and the market is homogeneous. It is thin when the properties differ much, because with three data points a single bad comp moves the answer by a third.
How many comps should a CMA have?
Three to six closed sales, plus context from active, pending and expired listings. The solds establish value; the actives show current competition; the pendings show the freshest agreements; the expireds show where the market refused to go.
Do more comps make a valuation more accurate?
Only up to a point, and only if quality holds. Adding a seventh and eighth comparable typically means the screen was loosened to find them, and weaker comparables widen the indicated range rather than tightening it. Six strong comps beat twelve mixed ones.
Why are appraisers using fewer comps than they used to?
FHFA data shows the share of appraisals with five or more comps fell from 76% in 2013 to 59% in 2021. The published analysis documents the trend without settling its cause; plausible contributors include tighter inventory leaving fewer recent similar sales available, and changes in appraisal workflow and technology.
Sources
- FHFA, "Counting Comps: Exploring the Number of Comparable Properties in Home Appraisals," based on the Uniform Appraisal Dataset Appraisal-Level Public Use File — a 5% nationally representative random sample of appraisals from 2013 through 2021. About 13% of appraisals included exactly three comps; about 19% four; about 68% five or more (roughly 28% five, 29% six, 10% seven or more). Average and median: five. Share with five or more fell from 76% in 2013 to 59% in 2021. By state, the share ranged from 34% in Mississippi to 90% in California. The share was about 13 percentage points lower in rural areas than in high-density urban areas.
- Fannie Mae Selling Guide B4-1.3-08, "Comparable Sales" (effective 06/04/2025) — "A minimum of three closed comparables must be reported in the sales comparison approach." Contract offerings and current listings can be used as supporting data where appropriate.
- The explanation for the declining comp count is not established in the FHFA analysis; contributing factors named here are plausible interpretations, not findings.