Inflation Calculator

How it works

Historical purchasing power versus a scenario

The historical inflation mode uses the stated US CPI series and supported dates. The scenario mode instead applies an inflation rate that you choose. Keep these purposes separate: a scenario is not a forecast from the historical dataset. Compare the amount in its original date's money with the equivalent amount at the target date to understand the change in purchasing power.

Historical US CPI purchasing power: formula and assumptions

Equivalent amount=original amount×CPI(to)/CPI(from).

Uses BLS CPI-U all items, US city average, not seasonally adjusted. Data through August 2026, released September 11, 2026. October 2025 is unavailable in the official series and is not imputed.

Inflation scenario: formula and assumptions

Future equivalent = amount×(1+inflation)^years; purchasing power = amount/(1+inflation)^years.

This is a forward scenario, not a historical CPI lookup.

Worked example

Reference example currency: USD. These fixed examples do not change with your calculator preferences.

Using the Historical US CPI purchasing power example:

Amount (USD)

100

From month

2000-01

To month

2026-08

Equivalent amount=original amount×CPI(to)/CPI(from).

Example result

• Official CPI-U snapshot through 2026-08; latest release 2026-09-11. This national index is not a measure of every household’s personal inflation.

These are illustrative inputs. Change the values to explore a different scenario.

What to keep in mind

Historical calculations use a versioned BLS dataset. Future scenarios use your assumed rate; they are not forecasts.

Formula references

• CFPB: understanding mortgages (opens in a new tab)
• Investor.gov: financial tools and calculators (opens in a new tab)
• BLS CPI-U all items, US city average (CUUR0000SA0) (opens in a new tab)

References explain the underlying methods; they do not imply endorsement or individual professional review of Finflo.

Common questions