Which US house price index is the most accurate?

None is more accurate than the others; they measure different things. Case-Shiller and FHFA are the most rigorous for measuring change over time, while Zillow and Redfin give the most current picture of price levels.

Why is the Case-Shiller index published two months late?

It is built from recorded deeds and uses a three-month moving average, so the value labelled for a given month reflects closings from roughly the preceding three months.

What is the difference between FHFA and Case-Shiller?

FHFA uses only conforming conventional mortgages bought by Fannie Mae and Freddie Mac, excluding cash and jumbo purchases. Case-Shiller includes all financing types but weights large metros more heavily.

Can I compare the index values directly?

No. Each index uses a different base period, so the levels are not comparable. Only the percentage changes over the same window can be compared.

Six US house price measures compared

The United States has no single house price number. Six widely quoted measures — Case-Shiller, FHFA, Zillow, Redfin, Freddie Mac and Fannie Mae — are built from different homes, different transactions and different methods, and they can disagree by several percentage points at the same moment.

At a glance

Measure	Latest	Period	Published by	Frequency
Case-Shiller National (NSA)	336.66	Jun 2026	S&P Dow Jones Indices / CoreLogic	Monthly
FHFA House Price Index (national)	442.53	Jun 2026	Federal Housing Finance Agency	Monthly
Fannie Mae HPI (seasonally adjusted)	349.57	Q2 2026	Fannie Mae	Quarterly
Freddie Mac FMHPI (seasonally adjusted)	303.85	Jul 2026	Freddie Mac	Monthly
Zillow Home Value Index (ZHVI)	368,696.68 USD	Aug 2026	Zillow	Monthly
Redfin median sale price	398,596 USD	Aug 2026	Redfin	Monthly and weekly

How each one is built

Case-Shiller National (NSA): Method: Repeat-sales index: tracks price changes on the same home sold twice; Covers: Single-family homes bought with any financing, national and 20 metros; Released: About 2 months after the reference month
FHFA House Price Index (national): Method: Repeat-sales index built from mortgages bought or guaranteed by Fannie Mae and Freddie Mac; Covers: Only conforming, conventional mortgages — no cash buyers, no jumbo, no subprime; Released: About 2 months after the reference month
Fannie Mae HPI (seasonally adjusted): Method: Repeat-sales index from Fannie Mae loan and public deed records; Covers: National, weighted to all transactions rather than to Fannie loans alone; Released: About 1 month after quarter end
Freddie Mac FMHPI (seasonally adjusted): Method: Repeat-sales index from Freddie Mac loan records and public data; Covers: National, all 50 states and about 400 metros; Released: About 1 month after the reference month
Zillow Home Value Index (ZHVI): Method: Valuation model applied to the whole housing stock, not just homes that sold; Covers: A typical home in the 35th–65th percentile of value, national to ZIP level; Released: About 2 weeks after the reference month
Redfin median sale price: Method: The middle price among homes that actually closed — a level, not an index; Covers: Homes listed on the MLS in Redfin-covered markets; Released: Within about 2 weeks

Why the numbers disagree

Three of the six are repeat-sales indexes. They compare a home only with itself, which removes the effect of a change in the mix of homes sold — if a quiet month happens to contain more large houses, a median price rises even when no home got more expensive. That is the single biggest reason a median and an index can point in opposite directions in the same month.

The measures also cover different homes. FHFA sees only conforming conventional mortgages, so it misses cash buyers and the jumbo market and behaves more smoothly at the top of the market. Case-Shiller includes any financing but weights larger, more expensive metros heavily. Zillow does not require a sale at all: it values the entire stock every month, so it turns earliest and is the least affected by how many homes changed hands.

Which one to use

For the direction and size of price changes over time, use a repeat-sales index — Case-Shiller for the national headline most commentary refers to, FHFA when you need a long consistent history at state and metro level.

For what a home actually costs today in dollars, use Zillow ZHVI or the Redfin median sale price; an index number of 330 tells you nothing about affordability. For the earliest signal of a turn, Zillow and Redfin lead by roughly two months because they do not wait for deeds to be recorded.

Never compare index levels across the six. They use different base periods, so only their percentage changes are comparable.

Frequently asked questions

Which US house price index is the most accurate?: None is more accurate than the others; they measure different things. Case-Shiller and FHFA are the most rigorous for measuring change over time, while Zillow and Redfin give the most current picture of price levels.
Why is the Case-Shiller index published two months late?: It is built from recorded deeds and uses a three-month moving average, so the value labelled for a given month reflects closings from roughly the preceding three months.
What is the difference between FHFA and Case-Shiller?: FHFA uses only conforming conventional mortgages bought by Fannie Mae and Freddie Mac, excluding cash and jumbo purchases. Case-Shiller includes all financing types but weights large metros more heavily.
Can I compare the index values directly?: No. Each index uses a different base period, so the levels are not comparable. Only the percentage changes over the same window can be compared.