Inflation Calculator
Calculate inflation-adjusted purchasing power with official historical CPI data or a constant inflation assumption.
Use the official BLS CPI-U U.S. city average, all items, not seasonally adjusted. Dataset covers 1913 through September 2026.
Result
Source: BLS CUUR0000SA0, Index, 1982–84 = 100. Published annual averages are used directly, not recalculated from rounded monthly values.
How to use this calculator
Use the official BLS CPI-U U.S. city average, all items, not seasonally adjusted. Dataset covers 1913 through September 2026. Enter amounts in the units shown, select the applicable options, and click Calculate. Use Reset to restore the starting values.
Calculation formula
Adjusted amount = original amount × end CPI/start CPI.
Assumptions and accuracy
Review timing, rates, fees and result notes when comparing scenarios. Future returns and rates are assumptions rather than guaranteed outcomes. Monetary display follows the currency’s precision; intermediate calculations retain additional digits.
Choose what to calculate
Inflation calculator using historical CPI
Compare purchasing power using bundled BLS CPI-U data. Future inflation is an entered assumption; missing historical observations are not invented.
Open this calculationUnderstanding this calculation
Adjust money using historical CPI ratios, custom index values or an assumed forward/backward inflation rate. The relevant comparison is purchasing power, not an investment return.
Worked examples
Adjust purchasing power using two CPI index values
Illustrative inputs are specified in the steps below; the example link loads the complete settings. Unmentioned settings use the linked defaults.
- The index ratio is 150 / 100 = 1.5. An initial 1,000 requires 1,500 at the later price level.
Equivalent purchasing-power amount: 1,500 USD.
Try these inputsCommon questions
How do I convert old money into today's purchasing power?
Use the ratio of the end index to the start index, or select the appropriate available historical periods.
Is average CPI inflation my personal inflation rate?
No. Your spending categories and location can produce a different change in living costs.
Scope and assumptions
Historical data coverage is limited to the included dataset. CPI is an aggregate price measure and may differ from your personal spending pattern.
Sources
- Calculation methodology, rule versions and testing limitations
- Reference calculator for feature comparison (not a model-parity certification)
Calculation notes checked . Examples are mathematical checks under the stated assumptions.
Calculation methods and formulas
Historical CPI
Use the official BLS CPI-U U.S. city average, all items, not seasonally adjusted. Dataset covers 1913 through September 2026.
Adjusted amount = original amount × end CPI/start CPI.
Future Value
Adjust purchasing power with a constant annual inflation assumption.
Adjusted amount = amount × (1 + inflation)^years; divide to work backwards.
Past Value
Adjust purchasing power with a constant annual inflation assumption.
Adjusted amount = amount × (1 + inflation)^years; divide to work backwards.
Custom CPI Indexes
Convert using two explicitly supplied CPI values from the same series.
Adjusted amount = original amount × end CPI/start CPI.
See our calculation methodology and review status for data versions, rounding and validation limitations.