Key dates
Documents to gather
Collect the records that apply to you before starting your return.
Expenses you can usually claim
These may be allowable where incurred wholly and exclusively for your business. Keep evidence, apportion mixed-use costs and check the rules for your circumstances.
Expenses you cannot claim
- Client entertaining
- Fines and penalties
- Everyday personal clothing
- Ordinary commuting
The £1,000 trading allowance
If eligible, you can deduct up to £1,000 from gross trading income instead of claiming actual business expenses for that trade. You cannot claim both the allowance and actual expenses for the same trade.
If gross trading income is £1,000 or less, you may not need to tell HMRC about it, but exceptions apply. Compare the allowance with your actual allowable expenses before deciding which route to use.
Payments on account
These are advance payments towards the following tax year. They generally apply if your Self Assessment bill is over £1,000 and less than 80% of the tax you owe was collected outside Self Assessment. Each payment is normally half of your previous year’s Income Tax and Class 4 National Insurance bill.
General information for the 2025/26 UK tax year, not personalised tax advice. Eligibility, deadlines and amounts depend on your circumstances. Check current HMRC guidance or speak to a qualified adviser before filing.