Inflation: Frequently Asked Questions

What is the RPI?

The Retail Prices Index (RPI) measures the change from quarter to quarter in the price of the goods and services purchased by an average household in Jersey. The index is compiled using a large and representative selection of over 500 separate goods and services, with price movements for each measured at a representative range of outlets.

The RPI is the main measure of inflation in Jersey and is commonly used in private contracts for the uprating of maintenance payments and housing rents. It is also used in wage negotiations. It is sometimes referred to as the "Cost of Living", although strictly speaking it is not a cost of living index.

What is RPI(X)?

RPI(X) is the underlying rate of inflation. It is the RPI excluding mortgage interest payments.

Where can I find RPI data?

RPI and RPI(X) data, including index figures and percentage changes can be found on the Retail Prices Index page. Quarterly RPI reports are available to view on the RPI reports page.

How do I calculate the percentage change in prices between two periods in time?

RPI index figures should be used with this formula:

[(Later date RPI - Earlier date RPI)/ Earlier date RPI]x100

Alternatively, for dates from 1989 onwards you can use the Inflation calculator 

How do I re-value a sum of money?

For example, how do you work out how much maintenance payments or rent has gone up between two dates if these are to be adjusted using the RPI?

RPI index figures should be used with this formula:

Sum of money (£) x (Later date RPI/ Earlier date RPI)

Alternatively, for dates from 1989 onwards you can use the Inflation calculator