Understanding Inflation: What It Is and How It’s Calculated

Understanding Inflation: What It Is and How It's Calculated


Inflation is a term that often appears in financial news and economic discussions. However, for many people, the concept can be somewhat abstract. In this blog post, we'll demystify inflation in simple terms, explaining what it is and how it's measured in the UK. But, why is this information relevant to you? Understanding inflation is crucial because it impacts your purchasing power and, ultimately, your cost of living.

What Is Inflation?

Inflation is the rate at which the average price level of a basket of selected goods and services in an economy increases over a period of time. In simpler terms, it represents how much more you're paying for the same goods and services compared to a previous time frame. When inflation is occurring, your purchasing power - the amount you can buy with your money - is decreasing.

For example, let's say we have an inflation rate of 2%. A pack of gum that cost £1 last year would cost you £1.02 this year. So, the higher the inflation rate, the more you're paying for the same items over time.

How Is Inflation Calculated in the UK?

Inflation calculation in the UK utilises two key measures - the Consumer Price Index (CPI) and the Retail Price Index (RPI).

1. Consumer Price Index (CPI):

This is the primary measure of inflation in the UK. The CPI reflects changes in the cost of a typical basket of goods and services that households purchase, which covers a wide range of items including food, transportation, and housing, among others.

2. Retail Price Index (RPI): 

The RPI is an older measure of inflation. It differs from the CPI in that it includes housing costs like mortgage interest payments and council tax. While it provides a broader scope, many economists and statisticians don't consider it as reliable as the CPI, leading to its reduced usage.

So, how does the calculation work? Essentially, statisticians determine a "basket" of common goods and services people might buy, such as bread, milk, or a haircut. They then track how the total cost of this basket changes over time. The rate at which the cost of this basket increases from year to year is the inflation rate.

For instance, if the basket costs £100 this year and £102 the following year, then the inflation rate is 2%.

Who Measures and Reports Inflation?

In the UK, the Office for National Statistics (ONS) and the Bank of England are responsible for measuring and reporting inflation. These institutions monitor the prices of thousands of goods and services across the country to compute inflation rates.

A Note on Personal Experience of Inflation

Finally, it's important to remember that everyone's experience of inflation can vary as we all purchase different items. Hence, the inflation rate is an average figure and might not perfectly represent your personal cost of living changes.


Understanding inflation is vital because of its influence on our everyday lives. Knowing how it's calculated in the UK can help us grasp financial news, make informed decisions, and even shape our personal and business strategies.

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