How this calculator works
The ending CPI divided by the starting CPI measures the change in the price level. Multiplying your starting amount by that ratio gives an equivalent ending-period amount. The default context is Canadian all-items CPI, with observations supplied by you. A falling index gives deflation. No live CPI values or annualized rate are inferred.
Formula
q = ending CPI / starting CPI; equivalent amount = starting amount × q; cumulative inflation = q - 1, displayed as a percentage. Both index observations must be positive and comparable.
Worked example
If CPI rises from 100 to 125, $100 in the starting period corresponds to $125 in the ending period, a cumulative increase of 25%. Reversing those observations turns $100 into $80, a decrease of 20%.
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Frequently asked questions
Can I mix Canadian and US CPI?
No. Use one geography and consistent series, basket concept, index reference base and seasonal-adjustment treatment for both observations.
Should I compound the inflation rate again?
No. The ratio of the supplied indexes already captures the cumulative price change between those periods.
Does CPI describe every household's spending?
It describes a representative basket. Your personal price changes can differ if your spending pattern differs from that basket.