Calculate the effect of inflation on money
Calculating the effect of inflation on money scales an amount by the change in a price index between two years. The Inflation Calculator offers past-to-present, present-to-past and custom-rate modes. CPI modes use adjusted = amount × (CPI_target / CPI_source).
Custom-rate mode uses amount × (1 + rate)^years when a constant rate is assumed. QuickCalculators reports adjusted value and the cumulative percent change where available.
A past $100 purchase can require nearly twice as many present dollars after decades of inflation, depending on the years chosen and the index path.
Find what a past amount is worth today
Finding what a past amount is worth today multiplies the past figure by CPI_now / CPI_then. The Inflation Calculator past-to-present mode performs that scaling with data through 2025. Enter the historical amount, the source year and the target year.
The result answers how many present dollars match that earlier purchasing power. QuickCalculators keeps the years visible so the adjustment window is not ambiguous.
This mode fits nostalgia price comparisons, wage history discussions and historical cost benchmarks.
Find what today's money was worth in the past
Finding what today's money was worth in the past reverses the ratio: amount × (CPI_then / CPI_now). The Inflation Calculator present-to-past mode uses that path with data through 2025. A present $100 can represent much less purchasing power when rolled back to an earlier year.
QuickCalculators frames the answer as past-year dollars equivalent to the present amount.
Use this mode when restating a current budget line in the currency of a prior decade.
Use a custom inflation rate
Using a custom inflation rate projects adjustment without relying on historical CPI rows. The Inflation Calculator custom-rate mode compounds amount × (1 + rate)^years. A 3% custom rate over 10 years multiplies purchasing-power-adjusted need by about 1.34. Planning scenarios often use a round assumed rate rather than a specific CPI history.
QuickCalculators separates this mode so assumptions stay intentional.
Custom rates are forecasts or planning inputs, not measured historical inflation for specific years.
Read the cumulative inflation
Reading the cumulative inflation converts the price-level change into a percent over the selected span. The Inflation Calculator reports that cumulative figure alongside the adjusted dollars when CPI points exist for both years. Cumulative inflation can look large even when average annual rates look mild, because compounding stacks across decades.
QuickCalculators pairs both views - dollars and percent - so neither hides the other.
Always treat CPI coverage as data through 2025; years beyond that snapshot need updates or custom-rate planning.
Read the disclaimer
QuickCalculators labels Inflation Calculator results as estimates for information only. The Inflation Calculator does not provide financial, tax or investment advice. CPI categories, regional indexes and future inflation sit outside any single table with data through 2025.
Correct a common misconception: inflation means everything rose by the headline rate
A common misconception is that a 3% headline inflation rate means every price rose 3%. CPI is a weighted basket; food, rent and electronics move differently. The Inflation Calculator scales a generic amount by the index or custom rate entered, not by category-level prices.
Frequently asked questions
What does the Inflation Calculator do?
The Inflation Calculator adjusts an amount between years using CPI ratios or a custom inflation rate on QuickCalculators, with CPI data through 2025.
How is past-to-present inflation calculated?
Past-to-present inflation scales amount × (CPI_present / CPI_past). The Inflation Calculator applies that ratio for the selected years.
What does "data through 2025" mean?
Data through 2025 means the CPI table used on QuickCalculators covers historical values through calendar year 2025. Later years need updated data or the custom-rate mode.
When should a custom rate be used?
A custom rate should be used for planning assumptions or when CPI rows for the requested years are unavailable. The Inflation Calculator custom-rate mode compounds at the entered annual percent.
Summarize the Inflation Calculator
The Inflation Calculator converts amounts across time with CPI modes (data through 2025) or a custom rate, reporting adjusted dollars and cumulative change. QuickCalculators labels results as estimates, not advice.