Cumulative inflation
The total, compounded change in prices between two dates.
2 min read · Reviewed September 2026
In plain words
Cumulative inflation is the total price rise over a multi-year period. You can't just add annual rates — you must compound them. If prices rose 2%, 8%, 4%, and 3% over four years, the cumulative change is (1.02 × 1.08 × 1.04 × 1.03) − 1 ≈ 18.5%.
Frequently asked questions
How do I calculate cumulative inflation?
Multiply annual price index factors together: (1 + r₁) × (1 + r₂) × ... − 1. Or simply divide the CPI in the end year by the CPI in the start year and subtract 1. The InflationTheGuide calculator does this automatically.
Further reading