AgentCOS / Buyer's guide · Updated October 25, 2026
Best real estate data sources: where to get housing statistics you can quote
The best real estate data sources tell you who measured what, where, and when, so you can quote a housing statistic and defend it. This guide compares the free real estate data sources agents use most (Realtor.com, Redfin, Zillow, NAR, Freddie Mac, FHFA, Case-Shiller, the Census Bureau) plus ATTOM and Colorado's local reports, with what each measures, how often it updates and what it costs.
Full disclosure: AgentCOS sells the report named in this guide, and AgentCOS is owned by Brian Lee Burke. We name other tools fairly, using only what their own websites say. Prices were checked on October 25, 2026 and change often; confirm on each company's page before you buy.
Short answer
For listings and inventory, use Realtor.com's research data. For home values down to the ZIP, use Zillow's ZHVI or FHFA's House Price Index. For sales, NAR's Existing-Home Sales each month. For rates, Freddie Mac every Thursday. For long-run price trends in big metros, Case-Shiller. For your own market, your MLS and your association's monthly report beat every national source. Pick one source per number and stay with it; mixing sources is how two agents quote two different medians for the same month.
How we judge
Six checks for choosing
“Best” depends on what you need. These are the checks we use, the same for every option, ours included.
1. Who measured it, and how
Listing data, closed sales, appraisals and repeat-sales indexes all measure different things. Know which one you are quoting.
2. Sold or listed
A median list price is not a median sale price. Say which one, every time.
3. Geography that fits the question
National numbers for the news; metro, county and ZIP for a client. Use the smallest area the source supports well.
4. How fresh it is
Weekly, monthly or quarterly, and how far behind. Case-Shiller runs about two months behind; Freddie Mac is weekly.
5. Revisions
Many sources revise prior months. Quote the date you pulled it, and do not compare a revised month with a first release.
6. Terms of use
Free to read is not always free to republish. Check the publisher's terms before you put their numbers in your marketing.
Side by side
The comparison
From each company's own website, checked October 25, 2026. Listed in no particular order; this is not a ranking. On a phone, swipe the table sideways.
| Source | What it measures | Area and update | Cost |
|---|---|---|---|
| Realtor.com research data | Homes for sale, list prices, days on market, price cuts. | U.S., state and metro; monthly. | Free. |
| Redfin Data Center | Sales, prices, inventory and more. | Dashboards; the Housing Market Tracker updates weekly and monthly. | Free. |
| Zillow Research (ZHVI, ZORI) | Typical home values and rents. | State down to ZIP and neighborhood. | Free download. |
| NAR Existing-Home Sales | Existing-home sales and median sale price. | U.S. and 4 regions; monthly, near mid-month. | Free to read; check NAR's terms to republish. |
| Freddie Mac PMMS | Average 30-year and 15-year mortgage rates. | U.S.; weekly, Thursdays at noon ET. | Free. |
| FHFA House Price Index | Repeat-sales home prices. | U.S. down to ZIP and tract; monthly and quarterly. | Free. |
| S&P Cotality Case-Shiller | Repeat-sales home prices. | U.S., 20-city and 10-city (Denver included); monthly, about two months behind. | Free to read. |
| Census new construction and new home sales | Permits, starts, completions; new home sales and prices. | U.S. and regions; monthly. | Free. |
| ATTOM | Foreclosure filings and property data. | U.S., state, metro, city; monthly and quarterly reports. | Reports free to read; data licensing paid. |
| Colorado REALTORS and DMAR | Local sales, prices, supply. | Colorado statewide and by county (CAR); 11 Denver-area counties (DMAR); monthly. | CAR free; DMAR member-only. |
Option by option
What each one is good at
- Realtor.com research data. Monthly inventory, list price and days-on-market files. Realtor.com changed its method in October 2022, so new downloads do not line up with older ones. AgentCOS statistics pages read these files directly. Their page
- Redfin Data Center. Free dashboards; the Housing Market Tracker updates weekly and monthly, and most others monthly, with a few quarterly. Their page
- NAR Existing-Home Sales. The monthly national number reporters quote, released close to mid-month. October 2026 data is scheduled for Thursday, November 12, 2026 at 10 a.m. ET. Their page
- Freddie Mac PMMS. The weekly average mortgage rate survey, out Thursdays at noon ET (Wednesday when Thursday is a holiday). Their page
- FHFA House Price Index. Free repeat-sales price indexes from the nation down to ZIP codes and census tracts. The next quarterly release, covering the third quarter of 2026, is November 24, 2026. Their page
- Census new residential construction. Building permits, housing starts and completions, monthly. October 2026 data is scheduled for November 18, 2026. Their page
Honest fit
Where the AgentCOS AgentCOS statistics pages fits
- AgentCOS statistics pages pull Realtor.com listing data and Freddie Mac rates straight from the publisher every day, with the source and date beside each number.
- Every state has its own page, with metro tables, payment math and local notes, free to read and link to.
- When a client needs their own area, the $29 Area Market Report turns your MLS export into a branded report.
- In Colorado, The Kenna Group publishes sourced Denver-area statistics pages on kennarealestate.com, linked below.
When to pick something else
- We are not a primary source. We republish and explain other publishers' numbers, and we link to them.
- No ZIP-level national data on our pages yet. Use Zillow Research or FHFA for that.
- No bulk data or API. ATTOM and the publishers above license data.
- Your MLS is the best source for your own market. Our statistics pages use public publisher data, not MLS exports.
Questions
Quick answers
What is the best source for real estate data?
It depends on the number. Realtor.com for listings and inventory, NAR for existing-home sales, Freddie Mac for mortgage rates, FHFA or Case-Shiller for price trends, Zillow for home values by ZIP, and your MLS or association for your own market.
Where can I get free housing data by ZIP code?
Zillow Research publishes free home value (ZHVI) and rent (ZORI) files down to the ZIP, and FHFA publishes its House Price Index down to ZIP codes and census tracts.
Why do housing statistics from different sources disagree?
They measure different things: list prices or sale prices, all homes or repeat sales, MLS areas or county lines, first releases or revised months. Pick one source per number and say which one you used.
Is Case-Shiller the same as the FHFA index?
Both are repeat-sales price indexes, but they use different data. FHFA covers more areas, down to ZIP codes. Case-Shiller covers the U.S. and 20 large metros, including Denver, about two months behind.
Where can I find Denver real estate statistics?
The Kenna Group publishes a sourced Denver real estate statistics page and city pages on kennarealestate.com. The Colorado Association of REALTORS publishes free county reports, and DMAR publishes a monthly report for its members.
Can I put these numbers in my marketing?
Usually, with the source and date, but check each publisher's terms first. NAR, for example, asks non-members for written consent to reuse its data. MLS numbers follow your MLS's rules.
Sources
- Realtor.com research data. www.realtor.com
- Redfin Data Center. www.redfin.com
- Zillow Research data. www.zillow.com
- NAR Existing-Home Sales. www.nar.realtor
- Freddie Mac PMMS. www.freddiemac.com
- FHFA House Price Index. www.fhfa.gov
- S&P Cotality Case-Shiller 20-City index (FRED). fred.stlouisfed.org
- Census Bureau building permits release schedule. www.census.gov
- Census Bureau new residential sales. www.census.gov
- ATTOM foreclosure trends. www.attomdata.com
- Colorado Association of REALTORS market trends. www.coloradorealtors.com
- DMAR Market Trends. www.dmarealtors.com
Checked October 25, 2026. Prices and plans change; each company's own page is the final word.