What the FHFA House Price Index Measures, and Which Sales It Never Sees

The short answer

The FHFA House Price Index measures how the prices of the same single-family homes change between one sale (or refinance appraisal) and the next, using only homes with mortgages bought or guaranteed by Fannie Mae or Freddie Mac. That makes it a clean measure of price change for the conforming-mortgage market and a blind one for everything outside it: cash purchases, jumbo loans, FHA and VA loans, and most condos. Every figure on this site comes from it, so every figure inherits both properties.

Who publishes it

The Federal Housing Finance Agency, the regulator of Fannie Mae and Freddie Mac, has published the index since the 1990s with data back to January 1975. It is a federal statistical product in the public domain; the files are free to download from the FHFA datasets page.

How it is built

It is a weighted repeat-sales index. Rather than averaging the prices of whatever sold this quarter, which would swing with the mix of homes on the market, FHFA pairs each transaction with an earlier transaction on the same property and measures the change between them. The method is described in FHFA’s technical description. The result is a series where a value of 200 means prices are double what they were at the base period; the base itself is arbitrary and differs by file, so only ratios between two dates mean anything.

Which transactions are in it

Per the FHFA HPI FAQ, the index is based on transactions for single-family properties with conforming, conventional mortgages purchased or securitized by Fannie Mae or Freddie Mac. “Conventional” means not insured or guaranteed by FHA, the VA or another federal agency; “conforming” means within the loan limits those two companies can buy. So the following are not in the index:

• Cash purchases. No mortgage, no record.
• Jumbo loans. Above the conforming limit, so never sold to Fannie or Freddie. In expensive metros this is a large share of the market.
• FHA and VA loans. Government-insured, so not conventional. These skew toward first-time and lower-price purchases.
• Most condos and all multifamily. The index covers single-family properties.

In an area where many sales are cash or jumbo, the index describes a narrower slice of the market than the whole. It is still an honest measure of that slice.

Purchase-only vs. all-transactions

FHFA publishes two main flavors. The purchase-only index uses sale prices alone. The all-transactions index adds appraisal values from refinance mortgages to the sample, which gives it far more data points and lets FHFA publish it for many more areas: all 410 metro areas and divisions rather than the 100 largest, and the annual county and ZIP series, which exist only in the all-transactions flavor. This site uses all-transactions everywhere so that a ZIP answer and a state answer for the same house are built the same way. The trade-off is that appraisals are opinions, not sales, and they tend to lag the market at turning points.

Seasonal adjustment

FHFA publishes seasonally adjusted and unadjusted versions of the quarterly series. This site uses the unadjusted one, because your purchase happened in a particular quarter and the index for that quarter is the honest starting point. It means a spring-to-winter comparison carries a little seasonal noise; over the multi-year windows on the area pages it is small.

Why county and ZIP figures are called developmental

FHFA labels its county, ZIP-code and census-tract indexes “developmental”. They are annual rather than quarterly, they are built from far fewer transactions, they are revised as new data arrives, and where a year had too few sales FHFA reports no value at all. The county file currently covers 2,795 counties and the ZIP file 19,024 five-digit ZIPs, both through 2025 and last updated March 31, 2026. They are FHFA’s own figures and the most local ones available, which is why the calculator tries them first, and why it prints the label whenever it uses one and shows what the county, metro and state would have said instead.

How current it is

State and metro indexes are quarterly and are released about two months after the quarter ends; the master file currently runs through 2026 Q2. County and ZIP indexes are annual. So an estimate made from the ZIP index in the autumn is comparing your purchase to last December’s prices, while the state figure reaches the most recent quarter. Nationally, the index shows prices +3.0% over the last year (2025 Q2 to 2026 Q2) and +93.3% over ten (2016 Q2 to 2026 Q2).

What this guide does not cover

It does not compare FHFA’s index to the S&P Case-Shiller indexes or to brokerage price series, and it does not explain how FHFA weights the pairs. It also says nothing about any particular house: the index tracks an area, renovations and condition are invisible to it, and it is not an appraisal. To see the index applied to your own purchase, the home value since purchase calculator prints the exact values and periods it used.

Sources

• FHFA HPI frequently asked questions.
• FHFA HPI technical description.
• FHFA House Price Index datasets.

This guide is for informational purposes only. It is not an appraisal, and not financial, tax, lending or real-estate advice. Every estimate on this site tracks an area’s average, never a particular house. Confirm anything that matters with a licensed appraiser or your lender.

Last reviewed: September 2026 · Against the FHFA HPI FAQ and technical description, and the FHFA datasets page.