| Metric | Value | Confidence | Last Updated |
|---|---|---|---|
| CPI-U Index (August 2025) | 323.4 | 99% | October 2025 |
| Year-over-Year Inflation | ~2.5% | 99% | October 2025 |
| Fed Target | 2.0% | Reference | - |
One-liner: U.S. inflation is ~2.5% (YoY), with CPI index at 323.4 (1982-84=100 baseline).
Caveat: CPI measures urban consumers only (~93% of population); regional variation may differ significantly.
The Consumer Price Index (CPI) is the primary measure of inflation in the United States—tracking changes in the price level of a basket of consumer goods and services. The Bureau of Labor Statistics (BLS) produces this data monthly.
What the current numbers mean:
- A CPI of 323.4 means that goods costing $100 in 1982-84 now cost $323.40
- At 2.5% annual inflation, prices double approximately every 28 years
- Current inflation is near the Federal Reserve's 2% target
Inflation affects virtually every economic decision:
- Wages: Cost-of-living adjustments (COLAs) are tied to CPI
- Savings: Determines whether your money gains or loses purchasing power
- Interest Rates: The Federal Reserve adjusts rates based on inflation
- Contracts: Many business and government contracts escalate with CPI
- Policy: Trillions in Social Security, Medicare, and tax brackets adjust with CPI
A 1% change in CPI affects billions of dollars in annual adjustments.
| Period | CPI Index | YoY Inflation | Source |
|---|---|---|---|
| August 2025 | 323.4 | ~2.5% | BLS |
| June 2022 | 296.3 | 9.1% (peak) | BLS |
| 1982-84 Avg | 100.0 | Baseline | BLS |
| January 1947 | 21.5 | First obs. | BLS |
| Period | Average Annual Inflation |
|---|---|
| 1947-2025 (Full) | ~3.5% |
| 1990-2019 (Pre-COVID) | ~2.4% |
| 2021-2023 (COVID Surge) | ~6.0% |
| 2024-2025 (Current) | ~2.5% |
The BLS uses a Laspeyres price index:
CPI = (Cost of basket today / Cost of basket in base period) × 100
| Category | Weight | Examples |
|---|---|---|
| Housing | ~34% | Rent, utilities, furnishings |
| Food | ~14% | Groceries, restaurants |
| Transportation | ~16% | Vehicles, gas, insurance |
| Medical Care | ~9% | Healthcare, drugs, insurance |
| Recreation | ~5% | Entertainment, sports, hobbies |
| Education/Communication | ~7% | Tuition, phones, internet |
| Other | ~15% | Apparel, personal care |
Data Collection:
- ~80,000 prices collected monthly
- 75 urban areas across the U.S.
- Weights updated every 2 years from Consumer Expenditure Survey
| Measure | What It Is | FRED ID |
|---|---|---|
| Headline CPI | All items | CPIAUCSL |
| Core CPI | Excludes food & energy | CPILFESL |
| PCE | Fed's preferred measure | PCEPI |
| Core PCE | Fed's key target | PCEPILFE |
Why Core? Food and energy prices are volatile. Core inflation shows underlying trends.
Why PCE? The Federal Reserve targets PCE inflation rather than CPI because it accounts for substitution effects.
| Period | Peak Inflation | Cause |
|---|---|---|
| 1970s Stagflation | 14.8% (1980) | Oil shocks, monetary policy |
| Volcker Shock | Fed raised rates to 20%+ | Broke inflation cycle |
| Great Moderation | 2-3% (1990s-2000s) | Credible monetary policy |
| Great Recession | Brief deflation (2009) | Financial crisis |
| COVID Surge | 9.1% (June 2022) | Supply chain, stimulus |
| Current | ~2.5% (2025) | Fed tightening working |
| Component | Confidence | Explanation |
|---|---|---|
| Current CPI Index | 99% | Official government statistic, gold standard |
| YoY Inflation Rate | 99% | Direct calculation from CPI data |
| Historical Data | 99%+ | Fully verified, minimal revisions |
This is the most reliable inflation data available—produced by the U.S. government with rigorous methodology and complete transparency.
- Substitution bias: Fixed basket doesn't fully capture when consumers switch to cheaper alternatives
- Quality adjustment: Hard to account for product quality improvements over time
- New products: Slow to incorporate new goods (smartphones took years)
- Geographic variation: National average masks significant regional differences
- Population: Covers urban consumers only (~93% of U.S.)
Inflation Rate = ((CPI_now - CPI_1year_ago) / CPI_1year_ago) × 100
Real_value = Nominal_value × (CPI_target_year / CPI_original_year)
Example: $100 in 1984 equals ~$323 in 2025 purchasing power.
| Source | What It Provides | Link |
|---|---|---|
| Bureau of Labor Statistics | Official CPI (primary authority) | CPI Home |
| FRED | Easy API access to BLS data | CPIAUCSL |
Quick Access:
# Download latest CPI data from FRED
curl -L "https://fred.stlouisfed.org/graph/fredgraph.csv?id=CPIAUCSL" -o CPI-latest.csv| Document | Description |
|---|---|
| US-Inflation-CPI-1947-2025.md | Full dataset documentation |
| source.md | Detailed methodology |
| CPI-US-Monthly-1947-2025.csv | Monthly data (945 observations) |
| Attribute | Value |
|---|---|
| Research Date | October 2025 |
| Researcher | Kai |
| Method | Direct BLS/FRED data collection |
| Confidence Level | 99% (official government statistic) |
| Known Gaps | Pre-1947 data uses different methodology |
| Date | Change | Reason |
|---|---|---|
| December 2025 | Added SUMMARY.md with executive overview | Standardizing Substrate datasets to "Answer First" schema |
| October 2025 | Initial dataset creation | Comprehensive U.S. CPI data collection |
- BLS CPI FAQ - Common questions
- BLS Handbook of Methods - Full methodology
- Fed Inflation Target - Why 2%?
- CPI Inflation Calculator - BLS tool