What is the census?

The census in the UK is an essential survey that gives us the most accurate estimate of all people and households in the country. It is the largest survey in the country.

It’s the most complete source of information about our population that we have, and provides an incredibly detailed picture of our society.

At the Office for National Statistics (ONS), we’re responsible for planning and running the census in England and Wales. We work closely with the census offices in Scotland and Northern Ireland, who run their own censuses.

When does the census happen?

We hold the census every 10 years. It all started back in 1801 – so we’ve been doing this for over 200 years (except for 1941, during World War 2).

We ran our last census in 2011, and right now we’re busy getting ready for the next one in 2021.

Why is the census important?

In a nutshell, there’s no other survey that gives as much detail about us and the society we live in.

The information the census gives is vitally important to a lot of different people and organisations. These include local authorities and community groups in your area and nationwide, as well as the government, businesses, academics and genealogists.

Census data help these groups to understand our society and – in doing so – to help us. They use the information to find out what our needs are, and what those needs are likely to be in the future, to help with planning and resource allocation.

The census also provides a snapshot of how we live for future generations to look back on.

So what is information from the census used for?

Census information helps a wide range of people and organisations to do their work. Here’s a quick rundown of some of the main users and what they do with the data.

Your local authority and other public bodies

The census is very important to your local authority and others across the country. It’s also vital to the government and many other public sector organisations.

This is because it gives them the information they need to:

  • develop policies

  • plan and run services, such as schools, health services, roads and libraries

  • decide how to allocate funds to make sure public funds get to where they’re needed most

For example, census data showing how many people work in different jobs and industries are used to develop new job and training policies. And information on how people travel to work and how many cars they have contributes to planning roads and transport.


Lots of companies use census information to help them understand their customers. For example, a supermarket chain might use census population data to help decide where to open a new store.

Voluntary organisations

Voluntary organisations often rely on census data to get information about the communities they’re working in. They may also use census data as evidence to support any applications they make for funding.

Academics and students

Academics such as university professors often use census data to support research that they’re working on. And students use the data in a similar way to get the information they need for coursework and dissertations.

The public and genealogists

We can all use old census records for researching our family history – they’re released to the public 100 years after the census took place. The records provide a fantastic source of information we can use to find out more about our ancestors.