Many people were rushing to complete the census in England, Wales and Northern Ireland before the 21 March deadline.
Those who fail to complete the online form in time could face a £1,000 fine.
But those in Scotland needn’t worry, as the country has postponed its census due to the coronavirus pandemic.
The census has gathered information on every person and household in the UK since it was first introduced in 1801.
So, what is the census, when is the deadline in Scotland and why is it different?
Here is everything you need to know.
What is the census?
The census is a nationwide survey that takes place once a decade.
It’s an official count of every person and household in the UK, to provide the government and local authorities with vital information about who lives where and what they are employed as.
The data provides a “detailed snapshot” of society which helps authorities to make decisions on funding for services like schools, hospitals, roads and transport.
Census questions range from employment status and religion to gender and race, although some are voluntary.
All information gathered in the completion of the census is kept secure and confidential.
One person in each household needs to fill the census in, via an online or physical form, and failure to return or submit a completed one is a crime.
England, Wales and Northern Ireland’s 2021 version was the first digital census since the survey began in 1801.
The initial findings of the census will be published in March next year, while there will be another release 12 months later in March 2023.
When is the deadline in Scotland?
While the deadline to complete the census was Sunday 21 March for everyone living in England, Wales and Northern Ireland, Scotland has postponed its version due to the impact of the Covid crisis.
Instead, the deadline for those living in Scotland will be in March 2022.
The government said this was "the right decision for Scotland which will allow us to undertake a high quality and safe census in 2022".
Households in the country will have until this time next year to fill out the form.
Why is the deadline different?
The decision to postpone the census deadline in Scotland was announced by Cabinet Secretary for Economy, Fair Work and Culture Fiona Hyslop earlier this year.
She said: “Covid-19 is the biggest single public health challenge facing us in more than 100 years and as in many other areas of life, the ongoing disruption is impacting on the vital preparations for the census.
“Following careful consideration and on recommendation of National Records of Scotland, Ministers have informed the Scottish Parliament of their intention to move Scotland’s census date to March 2022.
"This reflects the unprecedented impact which COVID-19 is having across a wide range of sectors.
“We recognise Scotland’s Census remains more relevant than ever in the current climate, as it allows important planning decisions to be made informed by the make-up of Scotland’s population."