The Seasonally Adjusted CPI Was Up 0.649% in September

Here are the changes in the seasonally adjusted CPI for the six months ending in Aug: 

March 0.8651%

April 0.6400%

May 0.4729%

June -0.4220%

July 0.0737%

Aug. 0.3960 

 

See Consumer Price Index for All Urban Consumers: All Items in U.S. City Average from FRED (Federal Reserve Economic Data) compiled by the Research Division at the Federal Reserve Bank of St. Louis for data on the seasonally adjusted CPI.  

That site shows a graph but if you click on the Download button you will get the actual numbers in Microsoft Excel.

The Consumer Price Index for All Urban Consumers: All Items in U.S. City Average (CPIAUCSL) was 336.298 in Sept. and 334.131 in Aug. Since 336.298/334.131 = 1.00649, that means it was up 0.649%. If we had that every month for 12 months the CPI would be up 8.07%.  

It was 324.245 in Sept. 2025. Since 336.298/324.245 = 1.0371, that means it was up 3.71% over the last 12 months.

 

The non-seasonally adjusted CPI was 336.940 in Sept. and 324.800 in Sept. 2025. That was up 3.74%. So pretty close to the seasonally adjusted CPI. This is well above the Fed's target of 2.0% (although they prefer to use the Personal Consumption Expenditures Price Index which was 3.4% higher in Aug. 2026 than Aug. 2025).

 

For more information see Consumer prices rose 3.7% annually in September as gas prices skyrocket by Jeff Cox of CNBC. Excerpt:   

"The consumer price index, a broad measure of goods and services costs across the U.S. economy, rose a seasonally adjusted 0.6% for the month, putting the 12-month rate at 3.7%, the Bureau of Labor Statistics reported Wednesday. Economists surveyed by Dow Jones expected respective gains of 0.6% and 3.6%.

Stripping out volatile food and energy costs, the so-called core CPI rose 0.3% for the month and was up 2.6% on an annual basis, compared with respective estimates for 0.2% and 2.5%.

The annual rate for headline inflation was 3.4% in August while the core rate was 2.4%.

Surging energy costs were again the primary culprit in the inflation picture. The energy index jumped 5.2% as tensions continued between the U.S. and Iran in a war launched in late February that shows no signs of ending anytime soon."

The article also discusses what types of products are going up in price and what is going down. There is a graph of the monthly year-over-year percent change in prices and core prices going back almost 4 years. 

Related material: 

Consumer Price Index for All Urban Consumers: All Items Less Food and Energy in U.S. City Average (CPILFESL) This is also from from FRED (Federal Reserve Economic Data), compiled by the Research Division at the Federal Reserve Bank of St. Louis. It has the seasonally adjusted core CPI.

 

Consumer Price Index Data from 1913 to 2026

 

Personal Consumption Expenditures Price Index 

 

The Bureau of Labor Statistics makes seasonal adjustments. See Consumer Price Index Summary.

 

The table below has the annual inflation rate since 1914 in the columns labeled CPI %Ch. or CPI percentage change. It is from Consumer Price Index Data from 1913 to 2026 and is not seasonally adjusted. It is also the December to December change in the CPI. That site also looks at how the 12 month average for the CPI changed from one year to the next.

 

Year	CPI %Ch.		Year	CPI %Ch.		Year	CPI %Ch.		Year	CPI %Ch.
1914	1		1944	2.3		1974	12.3		2004	3.3
1915	2		1945	2.2		1975	6.9		2005	3.4
1916	12.6		1946	18.1		1976	4.9		2006	2.5
1917	18.1		1947	8.8		1977	6.7		2007	4.1
1918	20.4		1948	3		1978	9		2008	0.1
1919	14.5		1949	-2.1		1979	13.3		2009	2.7
1920	2.6		1950	5.9		1980	12.5		2010	1.5
1921	-10.8		1951	6		1981	8.9		2011	3
1922	-2.3		1952	0.8		1982	3.8		2012	1.7
1923	2.4		1953	0.7		1983	3.8		2013	1.5
1924	0		1954	-0.7		1984	3.9		2014	0.8
1925	3.5		1955	0.4		1985	3.8		2015	0.7
1926	-1.1		1956	3		1986	1.1		2016	2.1
1927	-2.3		1957	2.9		1987	4.4		2017	2.1
1928	-1.2		1958	1.8		1988	4.4		2018	1.9
1929	0.6		1959	1.7		1989	4.6		2019	2.3
1930	-6.4		1960	1.4		1990	6.1		2020	1.4
1931	-9.3		1961	0.7		1991	3.1		2021	7
1932	-10.3		1962	1.3		1992	2.9		2022	6.5
1933	0.8		1963	1.6		1993	2.7		2023	3.4
1934	1.5		1964	1		1994	2.7		2024	2.9
1935	3		1965	1.9		1995	2.5		2025	2.7
1936	1.4		1966	3.5		1996	3.3
1937	2.9		1967	3		1997	1.7
1938	-2.8		1968	4.7		1998	1.6
1939	0		1969	6.2		1999	2.7
1940	0.7		1970	5.6		2000	3.4
1941	9.9		1971	3.3		2001	1.6
1942	9		1972	3.4		2002	2.4
1943	3		1973	8.7		2003	1.9

 

Here is a timeline graph of this data: