# Should I use RPI or CPI?

## Should I use RPI or CPI?

The calculation method differs as the geometric mean is used in CPI, whereas the arithmetic means calculate RPI. In addition, RPI includes housing costs such as mortgage interest payments, which is not in the case of CPI computation. CPI is considered a lead indicator of inflation and thus has more relevance than RPI.

## Which is higher RPI or CPI UK?

The retail prices index rate of inflation typically comes out highest. In April 2022, RPI was higher than CPI: RPI ā 11.7% CPI ā 9.1%

How do you convert CPI to inflation?

First, subtract the CPI from the beginning date (A) from the later date (B), and divide it by the CPI for the beginning date (A). Then multiply the result by 100 to get the inflation rate percentage.

### Why is CPI higher than RPI?

The RPI index essentially does the same job as the CPI but typically tracks slightly higher. Its main point of difference is it includes mortgage interest payments, so it is more influenced by house prices and interest rates than the CPI, which does not.

### Why is CPI more accurate than RPI?

We believe that Retail Price Inflation (RPI) is a less effective measure of inflation and favour Consumer Price Inflation (CPI) for three key reasons; CPI is the accepted national standard for measuring inflation. The formula of RPI is flawed and leads to a long-term upward bias.

What is the formula for calculating inflation?

To calculate inflation, start by subtracting the current price of a good from the historical price of the same good. Then, divide that number by the current price of the good. Finally, multiply that number by 100 and write your answer as a percentage.

Table

Period Value
2019 3.3
2020 2.1
2021 2.9
1988 Q1 4.9

#### How is CPI and RPI measured?

The RPI is an arithmetic mean; the prices of everything to be included in it are simply added up and divided by the number of items. The CPI is a geometric mean; it is calculated by multiplying the prices of all the items together and then taking the nth root of them, where ānā is the number of items involved.

Why is CPI lower than RPI?

The immediate answer is that they include slightly different things: RPI includes the costs of housing (mortgage interest costs, house prices and council tax, for example) and is therefore heavily influenced by these things, while CPI does not.

## What is the best measure of inflation UK?

The Consumer Prices Index (CPI)
The Consumer Prices Index (CPI) is the main measure of inflation. It is produced in line with international standards and is the measure used for the Bank of England’s 2% inflation target.

## Why CPI is not a good measure of inflation?

In addition, the CPI is not a reliable measure of infla- tion over long time periods. Changes in procedures used by BLS to collect individual prices have made it difficult for analysts to compare CPI inflation data from earlier periods with data from the current period.

Is CPI the best measure of inflation?

The “best” measure of inflation depends on the intended use of the data. The CPI is generally the best measure for adjusting payments to consumers when the intent is to allow consumers to purchase at today’s prices, a market basket of goods and services equivalent to one that they could purchase in an earlier period.

### What is the RPI figure for September 2021?

4.9%
RPI inflation was 4.9% in September 2021 (Index: 308.6), up from 4.8% in the year to August 2021.

### Why is the RPI higher than CPI?

Why is RPI so much higher than CPI?