CPI-U, not seasonally adjusted: the TIPS reference CPI
How much have consumer prices changed in a year?
CPI-U for September 2026 was 336.940, 3.7% above a year earlier (stored by 500metrics on ); the TIPS reference CPI on is 334.98000.
CPI-U, change from the same month a year earlier
CPI-U, US city average, all items, not seasonally adjusted (1982-84 = 100)
Each point is one month; pointing at the chart shows its month and value. A month with no published index (October 2025 was never collected) leaves a hole in the line.
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Observed .
Right now
Consumer prices were 3.7% higher in September 2026 than a year earlier, against 3.0% in September 2025.
Reference CPIOurs, by Treasury's formula
November 2026: 334.98000 on to 336.87467 on .
October 2026: 333.91800 on to 334.94574 on .
Treasury publishes its own figures, which are the ones that apply.
Understanding the reference CPI
Where it stands today
CPI-U was 336.940 in September 2026 (1982-84 = 100), a change of 3.7% from a year earlier (ours).
How is the reference CPI worked out?
The principal of a Treasury Inflation-Protected Security moves with CPI-U, not seasonally adjusted, with a lag.
Read more
The reference CPI for day d of a month is the CPI-U of three months earlier plus (d - 1) divided by the number of days in the month, times the difference between the CPI-U of two months earlier and of three months earlier. It is truncated to six decimals and rounded to five (31 CFR part 356, appendix B). The reference CPI on this page is computed by 500metrics with that formula from the published CPI-U; Treasury publishes its own figures, which are the ones that apply. The change from a year earlier is ours, rounded to one decimal.
The numbers behind the chart
What is the reference CPI on each day of November 2026?From CPI-U of August 2026 and September 2026
| Date | Reference CPI |
|---|---|
| 334.98000 | |
| 335.04533 | |
| 335.11067 | |
| 335.17600 | |
| 335.24133 | |
| 335.30667 | |
| 335.37200 | |
| 335.43733 | |
| 335.50267 | |
| 335.56800 | |
| 335.63333 | |
| 335.69867 | |
| 335.76400 | |
| 335.82933 | |
| 335.89467 | |
| 335.96000 | |
| 336.02533 | |
| 336.09067 | |
| 336.15600 | |
| 336.22133 | |
| 336.28667 | |
| 336.35200 | |
| 336.41733 | |
| 336.48267 | |
| 336.54800 | |
| 336.61333 | |
| 336.67867 | |
| 336.74400 | |
| 336.80933 | |
| 336.87467 |
What is the reference CPI on each day of October 2026?From CPI-U of July 2026 and August 2026
| Date | Reference CPI |
|---|---|
| 333.91800 | |
| 333.95226 | |
| 333.98652 | |
| 334.02077 | |
| 334.05503 | |
| 334.08929 | |
| 334.12355 | |
| 334.15781 | |
| 334.19206 | |
| 334.22632 | |
| 334.26058 | |
| 334.29484 | |
| 334.32910 | |
| 334.36335 | |
| 334.39761 | |
| 334.43187 | |
| 334.46613 | |
| 334.50039 | |
| 334.53465 | |
| 334.56890 | |
| 334.60316 | |
| 334.63742 | |
| 334.67168 | |
| 334.70594 | |
| 334.74019 | |
| 334.77445 | |
| 334.80871 | |
| 334.84297 | |
| 334.87723 | |
| 334.91148 | |
| 334.94574 |
What was CPI-U in each month?36 months, with the change from a year earlier
| Month | CPI-U | Change from a year earlier |
|---|---|---|
| September 2026 | 336.940 | 3.7% |
| August 2026 | 334.980 | 3.4% |
| July 2026 | 333.918 | 3.4% |
| June 2026 | 333.952 | 3.5% |
| May 2026 | 335.123 | 4.2% |
| April 2026 | 333.020 | 3.8% |
| March 2026 | 330.213 | 3.3% |
| February 2026 | 326.785 | 2.4% |
| January 2026 | 325.252 | 2.4% |
| December 2025 | 324.054 | 2.7% |
| November 2025 | 324.122 | 2.7% |
| September 2025 | 324.800 | 3.0% |
| August 2025 | 323.976 | 2.9% |
Show 23 more rows
| Month | CPI-U | Change from a year earlier |
|---|---|---|
| July 2025 | 323.048 | 2.7% |
| June 2025 | 322.561 | 2.7% |
| May 2025 | 321.465 | 2.4% |
| April 2025 | 320.795 | 2.3% |
| March 2025 | 319.799 | 2.4% |
| February 2025 | 319.082 | 2.8% |
| January 2025 | 317.671 | 3.0% |
| December 2024 | 315.605 | 2.9% |
| November 2024 | 315.493 | 2.7% |
| October 2024 | 315.664 | 2.6% |
| September 2024 | 315.301 | 2.4% |
| August 2024 | 314.796 | 2.5% |
| July 2024 | 314.540 | 2.9% |
| June 2024 | 314.175 | 3.0% |
| May 2024 | 314.069 | 3.3% |
| April 2024 | 313.548 | 3.4% |
| March 2024 | 312.332 | 3.5% |
| February 2024 | 310.326 | 3.2% |
| January 2024 | 308.417 | 3.1% |
| December 2023 | 306.746 | 3.4% |
| November 2023 | 307.051 | 3.1% |
| October 2023 | 307.671 | 3.2% |
| September 2023 | 307.789 | 3.7% |
What do these figures leave out, and how are they cited?Limits, dates and how to cite
What this number cannot tell you
- A month with no published CPI-U (October 2025 was never collected, because of the lapse in appropriations) has no change from a year earlier, and no reference CPI is computed from it here.
- The record begins in January 1913; BLS revises seasonally adjusted figures, not the index shown here.
Observed . Checked .
How to cite this
U.S. Bureau of Labor Statistics, Consumer Price Index for All Urban Consumers (CPI-U), U.S. city average, all items, not seasonally adjusted, through September 2026. Reference CPI computed by 500metrics, "How much have consumer prices changed in a year?", https://500metrics.com/treasury/tips-reference-cpi.
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