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The Knowledge Base

Self Assessment Library

Every guide, checklist, and walkthrough we've published to help you conquer your UK tax return.

Self Assessment

HMRC Self Assessment Deadlines & Penalties 2026/27

Don't get hit with a £100 fine. See every critical date for registration, filing, and payment in the current UK tax year.

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Self Assessment

What Happens If You File Late? A Guide to HMRC Penalties and Mitigation

Missed the January 31st deadline? Discover what happens next, how much you'll be fined, and the specific steps you can take to stop the damage today.

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Self Assessment

What is a UTR Number? Your 10-Digit ID for HMRC Self Assessment

Everything you need to know about the Unique Taxpayer Reference (UTR) number in the UK. Learn what it is, where to find it, and why you need it for your tax return.

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Self Assessment

Allowable Expenses: Exactly What Can You Deduct to Lower Your Tax Bill?

Everything you need to know about HMRC-approved expenses for freelancers, sole traders, and side hustles. Learn how to legally lower your tax bill.

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Self Assessment

How to Register for Self Assessment: The Step-by-Step UK Guide

A plain-English walkthrough of the HMRC registration process. Learn exactly what you need, how long it takes, and how to get your 10-digit UTR number correctly.

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Self Assessment

Do I Actually Need to Register for Self Assessment UK Tax? (2026/27)

Take the 60-second test to find out if you need to tell HMRC about your income. Learn the thresholds for Vinted, Etsy, freelancing, and side hustles.

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Self Assessment

The £1,000 Trading Allowance: Your 'Free' UK Tax Pass

Everything you need to know about the UK's £1,000 Trading Allowance. Learn how to skip paying tax on your side hustle legally and when to claim it.

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Self Assessment

What is Self Assessment? The Beginner's Guide to UK Tax Filing

Everything you need to know about HMRC Self Assessment in plain English. Learn why it exists, who it's for, and how the process actually works.

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