CPI is the consumer prices index. It is the measure adopted by the Government for its UK inflation target. The Bank of England's Monetary Policy Committee is required to achieve a target of 2 per cent. Prior to 10 December 2003, the CPI was published in the UK as the harmonised index of consumer prices (HICP).
RPI is the retail prices index. The uses of the RPI and its derivatives include indexation of pensions, state benefits and index-linked gilts.
Inflation is the percentage change in the index compared with the same month one year previously.