A warning has been issued to everyone to complete their Census form by Sunday, or be left facing a hefty fine.
The issue was highlighted in the weekly moneysavingexpert newsletter, which said: "This Sunday is Census day, fill it in, or face a £1,000 fine".
The Census is a survey that happens every 10 years and gives a picture of life in England, Wales and Northern Ireland.
People can complete the census online by using the online code that should have been printed on your invitation letter, or alternatively you can ask for a form to be posted out to you.
It's an offence to supply false information or not to complete the census, and you could be fined up to £1,000.
However the Money Saving Expert website said: "Fines are a last resort though. In England and Wales, four people received the maximum £1,000 fine for non-compliance at the last census in 2011, while a further 270 people were fined an average of £218."
On the form most questions are compulsory and must be answered, however some are voluntary.
All questions except those on religion, sexual orientation and gender identity are compulsory.
Technically people should complete their Census on Sunday March 21, but you can do it earlier.
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The savings website said: "It's because this is the day being used as a snapshot of life in 2021.
"If you can't complete the form on the day itself, do so as soon as you can afterwards but fill it in based on your circumstances on 21 March.
"You can complete forms online until early May."
