Insights
Self Assessment insights
Practical notes on Self Assessment forms, deadlines, Making Tax Digital and how the software maps to HMRC pages.
Making Tax Digital for Income Tax 2026/27 — Who Must File Digitally
From 6 April 2026, sole traders and landlords over £50,000 gross income must keep digital records and send quarterly updates to HMRC.
6 April 2026
Self AssessmentSelf-Assessment Tax Return Deadlines 2025/26 — Key Dates You Must Know
The dates that matter for the 2025/26 tax year, from 6 April through payments on account.
6 April 2026
Error 1046 GuideError 1046 — What It Means and How to Fix It
HMRC validation error 1046 usually means a figure or box combination is inconsistent.
12 March 2026
Government GatewayHow to Add Taxes to Your Government Gateway Account
Self Assessment must be activated on your Gateway account before commercial software can submit.
2 February 2026
Government GatewayWhat Is a Government Gateway User ID and How Do You Get One?
Commercial software still needs a Gateway user ID even if you normally use One Login.
20 January 2026
EmploymentWhat is a P60 and Why Is It Important for Your Tax Filing?
Your P60 summarises pay, tax and National Insurance for the year — it drives SA102.
10 January 2026
EmploymentWhat is a P11D? A Guide for Employees
P11D reports benefits in kind such as company cars and private medical insurance.
8 January 2026
Self AssessmentResidence, Remittance (SA109)
SA109 covers residence, domicile, split year treatment and the remittance basis.
20 October 2025
Self AssessmentCan I amend my Self Assessment tax return after filing?
Yes — usually within 12 months of the 31 January deadline, after waiting 72 hours.
18 October 2025
Self AssessmentTrust Income (SA107)
Report income from trusts, settlements and deceased persons' estates.
15 October 2025
Self AssessmentForeign Income (SA106)
Overseas employment, property, savings, dividends and foreign tax paid.
14 October 2025
Self AssessmentProperty Income (SA105)
UK land and property, including Furnished Holiday Lettings in the UK and EEA.
13 October 2025
Self AssessmentPartnership Income (SA104)
Your share of trading or property partnership profits.
13 October 2025
Self AssessmentSelf Employment (SA103)
Business income, expenses, capital allowances and CIS deductions.
13 October 2025
Self AssessmentEmployment Income (SA-102)
Salary, bonuses, benefits and expenses from employment.
12 October 2025
Self AssessmentSelf Assessment (SA100)
The main return — personal details plus interest, dividends and pensions.
12 October 2025
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