Estimates of the population size in every local authority area will be published on Tuesday by the Office for National Statistics (ONS), along with a breakdown by age and sex.
There will also be figures showing the change in population since the last census in 2011.
The number of people living in England and Wales grew by a record 7% in the decade to 2011, to reach 56.1 million.
A similar leap in the 10 years from 2011 to 2021 would take the population to just over 60 million.
Every census held in England and Wales is different. The results from Census 2021 will provide a unique picture of population during the pandemic.
Learn more about upcoming results https://t.co/yblfhJQF16 pic.twitter.com/rs1ofzdcLa
— Census 2021 - England & Wales (@Census2021) June 25, 2022
Separate estimates by the ONS have already suggested the UK’s population in the 12 months to mid-2020 grew at the slowest rate in two decades, though this reflected the impact of only the first wave of the coronavirus pandemic.
More than 20 million households across England and Wales filled in census questionnaires in spring last year, with a record 89% of responses completed online.
This has provided data of “extremely high quality”, according to Jen Woolford, ONS director of health, population and methods transformation.
“The data will give us a crucial baseline from which to measure changes in our society, which will help us understand changing needs,” she added.
“It was important to understand the population and its characteristics during the Covid-19 pandemic and early census data has already been used to understand more about vaccine uptake by occupation and to support the response to the Russian invasion of Ukraine.”
In 1801, the population of England and Wales was 8.9 million.
That’s roughly what the population of London was in 2020.
Soon you will be able to look up the new number for how it changed in 2021. https://t.co/paCLK4VFJs
— Census 2021 - England & Wales (@Census2021) June 20, 2022
The census takes place across the UK every 10 years and provides the most accurate estimate of all the people and households in the country.
Its results are used by a range of organisations including governments, councils and businesses, and underpins everything from the calculation of economic growth and unemployment to helping plan schools, health services and transport links.
Data from the 2021 census for England and Wales will be published in stages over the next two years, the ONS said.
Future releases will include figures on ethnicity, religion, the labour market, education and housing plus – for the first time – information on UK armed forces veterans, sexual orientation and gender identity.
The first results from the 2021 census in Northern Ireland were published last month by the Northern Ireland Statistics and Research Agency.
They showed that the population on census day – March 21 2021 – was a record 1,903,100, up 5% since 2011.
This compares with 7% growth between 2001 and 2011.
In Scotland, the census is run by the National Records of Scotland and was delayed by one year because of the Covid-19 pandemic.
Data collection ended on May 31 and the first results are expected in 2023.