An eight-part series taking you from "do I even need to file?" through registering for a UTR, declaring income, claiming expenses, paying on account and amending after submission.
Most UK workers never need to do a Self Assessment. But about 12 million do. Here's the precise list of trigger conditions for 2024/25 and 2025/26 — and how to register if it turns out you do.
The complete checklist for whether you need to file a self assessment tax return in the UK: employment income, rental, freelance, savings interest, CGT, dividends and more.
Step-by-step guide to registering for Self Assessment, getting your UTR (Unique Taxpayer Reference) number, setting up your HMRC Government Gateway account and what to do if things go wrong.
Step-by-step guide to registering for UK self assessment online, what a UTR number is, how long it takes, and how to access your HMRC online account.
Part 3 of our Self Assessment series — how to declare employment, self-employed, dividend, rental, foreign, savings, crypto and CGT income on your UK tax return. With the boxes to fill, evidence to keep, and common errors.
Which boxes to fill in for each income type on your self assessment return: employment (P60/P11D), rental (SA105), dividends (SA101), CGT (SA108) and foreign income.
What you can and can't deduct as a sole trader on your Self Assessment. Home office, mileage, phone, subsistence, professional fees, capital allowances and the £1,000 trading allowance — with worked examples.
Which expenses you can claim against self-employment income on your UK tax return: AMAP mileage, WFH flat rate, equipment, training, marketing and more — with examples of what HMRC allows and disallows.
How to declare capital gains on your Self Assessment. Shares, crypto, second properties, the £3,000 annual exemption, 60-day property reporting, pooling rules and worked examples for 2025/26.
How HMRC calculates your self assessment tax bill: income tax at marginal rates, National Insurance for the self-employed, payments on account explained, and how to reduce your July bill.
How HMRC's payments-on-account system works, why your first January bill is bigger than expected, when to reduce them, and the trap of treating January and July as separate
Step-by-step walkthrough of completing the online self assessment SA100 form in 2026: every section, which supplementary pages you need, and how to check before submitting.
Making Tax Digital for Income Tax (MTD ITSA) starts April 2026 for £50k+ self-employed and landlords. Here's what it means, when it applies to you, the software requirements and how it changes Self Assessment forever.
What happens after you submit your UK self assessment return: how to get a refund, how to correct mistakes, what to do if HMRC opens an inquiry, and your rights.
What happens after you submit your Self Assessment return — refunds, balancing payments, amendments, HMRC enquiries, the SA302 for mortgages, and the 5-year record-keeping rule
The most common self assessment questions answered: missed deadline, HMRC notice to file, closing your account, moving abroad, inheritance, crypto, side hustles and more.
