CPI vs PPI
What consumers pay against what producers get paid, monthly since 2010. Five views of the same two indices: how far each has risen, the ratio between them, the size and speed of the gap, which one moves first, and whether they are moving together.
1Index levels
Both indices rebased so the first month with every series, , equals 100. The vertical distance between the lines is the cumulative difference.
CPI, all items (consumer)
PPI, final demand (producer)
2The ratio: PPI ÷ CPI
Above 100, producer prices have risen more than consumer prices since ; below 100, less. The level depends on the base month, so read the direction, not the number.
Headline ratio
Core ratio (both indices less food and energy)
3The gap, and how fast it is moving
Bars: 12-month PPI inflation minus 12-month CPI inflation, in percentage points. This is also the speed at which the ratio above is changing. The thin line is the same gap over only the last three months, annualized: when it sits above the bars, the gap is still widening; when it drops below, the two are converging.
Producers outpacing
Consumers outpacing
3-month speed, annualized (line)
4Who leads
How well a shift in PPI inflation lines up with a shift in CPI inflation k months later: the correlation of three-month changes in each 12-month rate, over the whole sample. A tall bar at k means PPI moves tend to show up in CPI about k months on.
Correlation at each lead
Secondary pass-through window (5–8 months)
5Together or apart
Rolling 24-month correlation of monthly percentage changes. It ignores the size of the gap and asks only whether the two indices move in the same direction month to month: near 1, in lockstep; near 0, independently.
24-month correlation
Context, as of the September 2026 releases
- September CPI rose 0.6% on the month and 3.7% over the year; core CPI 2.6%. Gasoline accounted for more than half of the monthly rise and is up 34.2% over the year.
- September PPI final demand rose 1.3% on the month, the largest gain since March 2022, and 6.3% over the year. Final demand energy rose 10.8% on the month; intermediate unprocessed goods are up 21.5% over the year.
- Federal Reserve projections of 16 September 2026 (PCE, not CPI): headline 3.7% for 2026 and 2.3% for 2027; core 3.4% and 2.5%; median policy rate 4.1% at the end of both years.
- Into 2027, a level-off in energy prices alone would pull the 12-month rates down as the year-ago comparison catches up. The open question in charts 3 and 4 is how much of the producer-price surge is still to reach consumer prices.
Hand-written context; the charts and tiles above update from data. Reference only, not investment advice.
Last 24 months as a table
| Month | CPI 12-mo | PPI 12-mo | Gap | 3-mo speed | PPI÷CPI |
|---|
Method and sources
- Data: U.S. Bureau of Labor Statistics via FRED. Series CPIAUCSL and PPIFIS (seasonally adjusted) for levels, the ratio, 3-month speed and correlation; CPIAUCNS and PPIFID (not seasonally adjusted) for the 12-month rates, matching the BLS headlines; CPILFESL and PPICOR for the core ratio.
- October 2025 CPI was never published (federal government shutdown). It shows as a break in charts 1–2 and is filled by geometric interpolation for the rate and correlation calculations.
- PPI covers goods and services sold by producers, including to businesses and government; CPI covers what urban households buy and is about one-third shelter, which PPI barely includes. That difference helped keep the gap negative through much of the 2010s, when rents rose faster than goods prices.
- Correlations describe co-movement, not cause. The lead/lag pattern and the gap episodes come from one sample with one comparable surge (2021–22).