Extended Chained Consumer Price Index for Urban Consumers (C-CPI-U)

The monthly, quarterly, or annual C-CPI-U series extended to 1937 through the present, based on CPI-U-RS, CPI-U, and CPI-U-X1.

c_cpi_u_extended_monthly_nsa

c_cpi_u_extended_monthly_sa

c_cpi_u_extended_quarterly_nsa

c_cpi_u_extended_quarterly_sa

c_cpi_u_extended_annual

Format

The extended C-CPI-U series uses the C-CPI-U since 2000 and extends it retroactively by merging it to the CPI-U-RS (1978-1999), CPI-U-X1 (1967-1977), and CPI-U (1966 and before).

The data frames c_cpi_u_extended_monthly_nsa and c_cpi_u_extended_monthly_sa contain, respectively, the not-seasonally and seasonally adjusted price index levels of the extended C-CPI-U. They have three columns:

year: numeric year
month: numeric calendar month (1-12)
c_cpi_u_extended: value of the C-CPI-U extended price index

The data frames c_cpi_u_extended_quarterly_nsa and c_cpi_u_extended_quarterly_sa are the quarterly versions of these series. They have three columns:

year: numeric year
quarter: numeric calendar quarter (1-4)
c_cpi_u_extended: value of the C-CPI-U extended price index

The data frame c_cpi_u_extended annual contains the annual price index level of the extended C-CPI-U. It has two columns:

year: numeric year
c_cpi_u_extended: value of the C-CPI-U extended price index

Source

The seasonal adjustment in c_cpi_u_extended_monthly_sa is simply a multiplication of the non-seasonally adjusted c_cpi_u_extended_monthly_nsa values by the ratio of the cpi_u_monthly_sa to cpi_u_monthly_nsa. The quarterly c_cpi_u_extended_quarterly_nsa and c_cpi_u_extended_quarterly_sa series are the quarterly means of their respective monthly series.

For months where CPI data was not published (e.g., October 2025), the monthly extended series values are linearly interpolated from the adjacent months' values. The quarterly series are then computed as usual from the monthly values including any interpolated months.

For annual statistics, the U.S. Census Bureau currently uses a similar combination of price indexes to extend the C-CPI-U: https://www.census.gov/topics/income-poverty/income/guidance/current-vs-constant-dollars.html.

Examples

c_cpi_u_extended_annual
#> # A tibble: 89 × 2
#>     year c_cpi_u_extended
#>    <dbl>            <dbl>
#>  1  1937              9.8
#>  2  1938              9.6
#>  3  1939              9.5
#>  4  1940              9.5
#>  5  1941             10  
#>  6  1942             11.1
#>  7  1943             11.8
#>  8  1944             12  
#>  9  1945             12.3
#> 10  1946             13.3
#> # ℹ 79 more rows