Side Hustle Income: When Do You Have to Declare It?
When a side hustle becomes taxable, the £1,000 trading allowance, when you need to register for Self Assessment, how online-platform reporting works, and when MTD might apply.
The short answer
You must declare side-hustle income once your gross trading income for the tax year exceeds £1,000 (the trading allowance). Below £1,000 it's usually tax-free and doesn't need reporting. Above it, register for Self Assessment and report the income; if your total gross self-employment (and property) income later exceeds the MTD threshold, MTD for Income Tax applies too.
Turning a hobby or side gig into cash is great — until you wonder whether the taxman wants a word. Here's exactly when a side hustle becomes something you must declare.
The £1,000 line
The key number is the trading allowance: you can earn up to £1,000 of gross trading income per tax year tax-free, with no need to report it. Go over £1,000 gross and you must declare the income.
"Gross" means before expenses — so it's your total takings, not your profit.
| Gross side-hustle income (tax year) | What to do |
|---|---|
| £1,000 or less | Usually tax-free, no need to report |
| Over £1,000 | Register for Self Assessment and declare |
Above £1,000: allowance or expenses
Once you're over £1,000, you deduct either the £1,000 allowance or your actual expenses — whichever gives the lower taxable profit. See our trading allowance guide for how to choose.
HMRC probably already knows
Online platforms — marketplaces, gig apps, short-let sites — now report sellers' income to HMRC under international rules. So HMRC may already have data on your side hustle. If you're over £1,000 and haven't declared, it's worth getting straight rather than waiting for a letter.
Registering for Self Assessment
If you cross £1,000, register for Self Assessment by 5 October following the end of the tax year you went over. You then report the income on your return (or, if applicable, through MTD).
When MTD comes into play
MTD for Income Tax applies once your total gross self-employment and property income exceeds the threshold — £50,000 from April 2026, dropping to £30,000 (2027) and £20,000 (2028). A small side hustle alone rarely reaches this, but it counts toward the total alongside your other income, so a growing side hustle can eventually bring you into scope.
Key takeaways
- Up to £1,000 gross side income a year is usually tax-free.
- Over £1,000, register for Self Assessment and declare it.
- Platforms report to HMRC, so don't rely on it going unnoticed.
- It counts toward the MTD threshold with your other income.
This article is general information, not tax advice. Check whether you need to report income at gov.uk or speak to your accountant.
Frequently asked questions
How much can I earn from a side hustle before paying tax?
Up to £1,000 of gross trading income per tax year is covered by the trading allowance and is usually tax-free with no need to report it. Once you go over £1,000 gross, you need to declare the income through Self Assessment.
Do the online platforms report my income to HMRC?
Yes. Digital platforms (marketplaces, gig and rental apps) report sellers' income to HMRC under international reporting rules. So HMRC may already know about income you haven't declared — another reason to report once you're over £1,000.
When do I register for Self Assessment?
Once your gross trading income exceeds £1,000 (or you have other reasons to file), register for Self Assessment by 5 October following the end of the tax year in which you crossed the threshold.
Could my side hustle fall under MTD?
If your total gross self-employment and property income exceeds the MTD threshold (£50,000 from April 2026, falling to £30,000 then £20,000), MTD for Income Tax applies. A small side hustle alone usually won't reach it, but it counts toward the total.
Related reading
MTD for Income Tax Explained for Sole Traders (2026 Guide)
A plain-English guide to Making Tax Digital for Income Tax for sole traders — who's affected, what changes, what you have to do each quarter, and how to get ready before April 2026.
Who Is Exempt from Making Tax Digital for Income Tax?
Who doesn't have to follow MTD for Income Tax: income below the threshold, digitally excluded people, and specific groups HMRC has exempted or deferred — plus how to apply for an exemption.
MTD for Income Tax Deadlines & Thresholds: 2026, 2027 & 2028
Every Making Tax Digital for Income Tax date and threshold in one place: who joins when, the £50k/£30k/£20k phases, quarterly update deadlines, and the final declaration cut-off.