Best Website for Real Estate Comps: 9 Sources, Ranked by the Job They Actually Do
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Short answer
It depends which of four jobs you have. Agents with MLS access: the MLS, then RPR (free with NAR membership) for the report. Homeowners: Redfin for sold data, your county assessor for verification. Investors screening at volume: PropStream or a similar deal-sourcing platform. Anyone who needs a document to hand someone else: a per-report CMA tool. The mistake is picking one site and using it for all four.
Every "best website for real estate comps" list has the same problem: it ranks nine tools against one imaginary user. In practice there are four users with genuinely different needs, and a source that is excellent for one is close to useless for another.
So this is sorted by job first, tool second.
First: what actually separates a good comp source from a bad one
Three things, and only three things, distinguish comp sources. Everything else is interface.
- Provenance. Is the price a confirmed closed sale, an estimate, or a list price that never happened? This is the single biggest quality gap between sources, and most sites do not label it clearly.
- Completeness of the record. Seller concessions, days on market, prior listing history, condition notes. A price without concession data can overstate what the market actually paid.
- Latency. How long after closing does the sale appear? Public-record-derived data can lag by weeks to months. In a moving market that lag is a pricing error.
If a source will not tell you whether a number is a confirmed sale price or a model output, treat it as a model output.
The non-disclosure problem, which nobody's roundup mentions
In roughly a dozen US states, the sale price of a home is not recorded in public records at all. Texas is one. Alaska, Idaho, Kansas, Louisiana, Mississippi, Montana, New Mexico, North Dakota, Utah, Wyoming and parts of Missouri are commonly on the same list.
This changes the ranking completely. In a non-disclosure state, every "free public records" method fails at the one thing you needed it for, and the MLS becomes the only authoritative source of closed prices. Any tool claiming a public-records-derived sale price in Texas is showing you an estimate, whether or not it says so.
Check your state before you trust a source. It is the fastest way to avoid a whole category of error.
Job 1 — You're a licensed agent with MLS access
1. Your local MLS — the answer, and it isn't close
Confirmed closed prices, concessions, DOM and CDOM, listing history, private remarks, photos. It is the source everything else is downstream of. If you have access and are using something else as your primary comp source, you are choosing worse data for a nicer interface.
Weakness: the report output is usually ugly, and it stops at your MLS boundary — a genuine problem for properties near a border where the real comps sit in a neighbouring system.
2. RPR (REALTORS Property Resource) — free, and underused
Included in NAR dues at no extra cost. Nationwide public-record data joined to MLS data, a comp selection and adjustment workflow, and a client-ready CMA output. For a solo agent who wants a decent report without a subscription, this is the obvious first stop and a surprising number of members have never logged in.
Weakness: the output is RPR-branded, not yours, and the workflow is heavier than most agents want under time pressure.
Job 2 — You're a homeowner or buyer with no MLS access
3. Redfin — best free source for sold data
Redfin is a brokerage, so it participates in MLS feeds directly. Sold listings are prominent rather than buried, and the filters (sold date, beds, baths, square footage, property type) are the closest a consumer site gets to running a real comp search.
Weakness: coverage varies by market — Redfin is stronger where it operates as a brokerage than where it does not.
4. Zillow — broadest coverage, noisiest signal
More records than anyone, including off-market properties Redfin will not show. The trap is that the Zestimate sits next to real sold prices in the same interface, and the two are not the same kind of number. See how accurate a Zestimate actually is, and how to pull comps on Zillow without picking up the estimate by accident.
5. Your county assessor or appraisal district — the verification layer
Free, authoritative on the physical facts — square footage, lot size, year built, ownership, assessment history — and in disclosure states, on sale prices too. This is where you check the square footage a listing site asserted, and it is the source a tax appeal board already trusts.
Weakness: no sale prices in non-disclosure states, records can be stale or wrong, and the interface is usually from 2004.
6. Realtor.com — useful third opinion
Operated under licence from NAR, so its listing data tends to be timely. Worth checking when Zillow and Redfin disagree, which happens more than you would expect.
Job 3 — You're screening properties at volume
7. PropStream and similar deal-sourcing platforms
Built for a different job entirely: finding properties, not presenting them. Large record counts, heavy filtering, distress signals, owner contact data. Priced around $99/month at the base tier.
If your job is to look at 400 properties and shortlist 12, this is the right category. If your job is to hand one seller a document, it is the wrong one — see PropStream vs. a brokerage-first comps tool.
8. Rental-specific tools
If the question is rent rather than sale price, general comp sites will not answer it. Rental comps are a separate dataset with separate rules — covered here.
Job 4 — You need a document, not a screen
9. Per-report CMA tools
The overlooked category. Every source above ends at a screen you have to interpret. If the actual deliverable is a branded PDF that a seller, a tax board or a lender will read without you in the room, none of the free sources produce one.
This is a different product category, priced per report or per seat, and the honest framing is that you are paying for presentation and consistency rather than for data nobody else has. Whether that is worth paying for depends entirely on whether the document leaves your hands.
The comparison, in one table
| Source | Confirmed sold prices | Cost | Best for |
|---|---|---|---|
| Local MLS | Yes | Board dues | Everything, if you have it |
| RPR | Yes (MLS-linked) | Free with NAR dues | Agents wanting a report free |
| Redfin | Yes, in disclosure states | Free | Homeowners, sold data |
| Zillow | Mixed with estimates | Free | Coverage breadth |
| County assessor | Disclosure states only | Free | Verifying the physical facts |
| Realtor.com | Yes, in disclosure states | Free | Third opinion |
| PropStream | Public-record derived | ~$99/mo | Investor screening |
| Per-report CMA tool | Depends on provider | Per report | A document you hand over |
The answer nobody wants: use two
Serious comp work uses one source for the price and a second, structurally different source to verify the property facts. MLS plus county records. Redfin plus assessor. The reason is not thoroughness for its own sake — it is that square footage discrepancies between MLS and tax records are common, and every adjustment you build on a wrong square footage inherits the error silently.
One source tells you a number. Two sources tell you whether the number is real.
The bottom line
There is no best website for real estate comps, because "comps" covers four jobs with different requirements. Pick by job. Verify the physical facts against a second source. Check whether your state discloses sale prices before trusting anything that claims to be one. And if the output has to leave your hands as a document, budget for that separately, because none of the free options produce it.
Frequently asked questions
What is the best free website for real estate comps?
Redfin is generally the strongest free source for sold-price data because it publishes closed sales prominently and lets you filter by sold status, date and property characteristics. Your county assessor or appraisal district site is the best free source for verifying square footage, lot size and ownership. In non-disclosure states, neither will show reliable sale prices, because those prices are not public record.
Is Zillow or Redfin better for comps?
Redfin is generally better for comp work. It is a brokerage with direct MLS participation, its sold-listing filters are easier to use, and its published accuracy figures for on-market homes have historically been competitive. Zillow has broader coverage and more off-market records. Most people should check both, because coverage differs by market.
Do real estate agents use Zillow for comps?
Not as the primary source. Agents pull comps from the MLS, which carries the confirmed closed price, seller concessions, days on market and remarks that public sites either lack or publish late. Agents commonly use Zillow or Redfin as a secondary check, or to see what a client has already seen before a listing appointment.
Can I get real estate comps without an MLS login?
Yes, but with a real accuracy cost. Redfin, Zillow, Realtor.com and county records will get a homeowner close in most disclosure states. What you lose is confirmed closed prices, concession data, and the private remarks that explain why a sale printed above or below the pattern.
What do appraisers use for comps?
Appraisers primarily use the MLS plus public records, and often a paid data service that aggregates both. Fannie Mae requires a minimum of three closed comparable sales in the sales comparison approach, with the appraiser responsible for selecting the most appropriate ones and explaining the selection.
Sources
- Fannie Mae Selling Guide B4-1.3-08, "Comparable Sales" (effective 06/04/2025) — minimum of three closed comparables in the sales comparison approach; distance reported in miles with a directional indicator; comparables closed within the last 12 months should be used.
- National Association of REALTORS® — RPR (REALTORS Property Resource) is included in NAR annual dues at no additional cost to members.
- Non-disclosure states, where sale prices are not recorded in public records, are commonly listed as Alaska, Idaho, Kansas, Louisiana, Mississippi, Missouri (some counties), Montana, New Mexico, North Dakota, Texas, Utah and Wyoming. Lists vary slightly by publisher because some states are partially disclosing.
- PropStream pricing of $99/month reflects its published base subscription and is referenced elsewhere in this blog; verify current pricing before relying on it.
- Vendor-published accuracy figures (Zillow, Redfin, Opendoor) are self-reported by interested parties and measured on their own methodologies. They are not independently audited and are not directly comparable to each other.