SELF ASSESSMENT 2025/26
Self Assessment Tax Return Guide
Your complete guide to filing Self Assessment tax returns in the UK. From registration to submission, we cover everything you need to know.
Paper Deadline: 31 October 2025
Online Deadline: 31 January 2026
Payment Deadline: 31 January 2026
Who Needs to File Self Assessment?
Self-employed individuals earning over £1,000
Company directors
Partners in a business partnership
Those with income from savings, investments or dividends
Landlords with rental income
Those earning over £100,000 per year
Those who need to pay Capital Gains Tax
Those receiving foreign income
How to Complete Your Self Assessment
1
Register for Self Assessment
Register with HMRC before 5 October following your first tax year of self-employment
2
Gather Your Records
Collect all income records, expense receipts, and previous tax information
3
Calculate Your Income
Add up all taxable income from self-employment, employment, and other sources
4
Claim Allowable Expenses
Deduct legitimate business expenses to reduce your tax bill
5
Complete Your Return
Fill in the Self Assessment form online or on paper
6
Submit and Pay
Submit by 31 January and pay any tax owed
Allowable Business Expenses
Office Costs
Stationery, phone bills, software subscriptions
Travel
Business vehicle costs, public transport, accommodation
Clothing
Uniforms, protective clothing (not everyday clothes)
Staff
Salaries, subcontractor costs, employer NICs
Financial
Insurance, bank charges, accountancy fees
Premises
Rent, utilities, repairs, business rates
Marketing
Advertising, website costs, trade subscriptions
Training
Professional development, relevant courses
Let TaxAce Handle Your Self Assessment
Avoid the stress and potential penalties. Our expert accountants will complete and submit your Self Assessment tax return accurately and on time.