You need to keep records if you have to send HM Revenue and Customs (HMRC) a Self Assessment tax return.
You'll need your records to fill in your tax return correctly. If HMRC checks your tax return, they may ask for the documents.
You must also keep records for business income and outgoings if you're self-employed.
How to keep your records
There are no rules on how you must keep records. You can keep them on paper, digitally or as part of a software program (like book-keeping software).
HMRC can charge you a penalty if your records aren't accurate, complete and readable.
Lost or destroyed records
Try to get copies of as much as you can, eg ask banks for copies of statements, suppliers for duplicate invoice etc.
You can use 'provisional' or 'estimated' figures if you can't recreate all your records. You must use the 'Any other information' box on the tax return to say that this is what you're doing.
'Provisional' means you'll be able to get paperwork to confirm your figures later. 'Estimated' means you won't be able to confirm the figures.
You may have to pay interest and penalties if your figures turn out to be wrong and you haven't paid enough tax.