🇬🇧UK Self-Employment Guide 2026

Everything you need to
know about going
self-employed.

A plain-English guide covering registration, tax deadlines, expenses, Making Tax Digital, and every mistake first-timers make.

5 Oct
Registration deadline (year 2)
31 Jan
Self Assessment & tax payment
25–30%
Of income to set aside for tax
6 years
HMRC can investigate back
The complete checklist

8 steps to get it right.

Follow these in order. Don't skip anything — each step builds on the last.

01
Register as Self-Employed with HMRCTime sensitive
⏱ 10 minutes
↓
You must register by 5 October in your second year of trading. Missing this deadline means an automatic £100 penalty.
What to do
1
Go to gov.uk/register-for-self-assessment
2
Select "I am self-employed" or "I have untaxed income"
3
You'll need your National Insurance number and contact details
4
HMRC will send your Unique Taxpayer Reference (UTR) by post within 10 working days
5
Your UTR is 10 digits — keep it safe, you'll use it forever
💡 MerxTax tip
Register as soon as you start earning — even if it's a side income alongside employment. The clock starts from your first pound earned, not when you decide to go full-time.
Register on GOV.UK →
02
Set Up Your National Insurance
⏱ 5 minutes
↓
03
Open a Separate Business Bank Account
⏱ 15 minutes
↓
04
Understand Your Tax DeadlinesTime sensitive
⏱ 2 minutes to learn, a lifetime to respect
↓
05
Know What Expenses You Can Claim
⏱ 20 minutes to learn
↓
06
Set Up Making Tax Digital (MTD)Time sensitive
⏱ 15 minutes
↓
07
Consider VAT Registration
⏱ 30 minutes
↓
08
Keep Records from Day One
⏱ Ongoing
↓

About MerxTax & MTD scope

  • Self-employment and UK/foreign property income. MerxTax supports MTD-mandated self-employment income and UK/foreign property income (quarterly updates and final declaration). Other income sources — employment, dividends, savings — are outside MTD scope here; use another HMRC-compatible product.
  • In-year quarterly updates and year-end Final Declaration. MerxTax covers in-year quarterly updates for MTD-mandated self-employment and UK/foreign property income, and the year-end Final Declaration for those sources. For income outside that scope, use another HMRC-compatible product.
  • In-year HMRC tax estimates are shown in VIGIL. MerxTax displays live in-year estimates from HMRC's Individual Calculations API — tap “Get HMRC estimate” in VIGIL once your HMRC account is connected. These are in-year figures; your final tax liability is confirmed by HMRC after your year-end declaration.

For the full list of HMRC-compatible MTD for Income Tax software, see HMRC's guidance on compatible software.

Built for self-employed people

MerxTax handles
all of this for you.

Quarterly MTD submissions, expense tracking, real-time tax liability, CIS deductions, and invoicing — all in one place. Designed for people who run a business, not for accountants.

📊
MTD Quarterly Submissions
Submit directly to HMRC. No accountant needed.
🧾
Receipt Scanning with AI
Photo your receipts. LUMEN categorises everything.
💰
Real-Time Tax Estimate
Always know what you owe. No January surprises.
📄
Invoicing (FACTURA)
Create and send professional invoices in seconds.
Common questions

Things people always ask.

Do I need an accountant?
+
What happens if I don't register?
+
Can I be employed AND self-employed at the same time?
+
What is a UTR number?
+
When do I have to start paying tax?
+
What is Making Tax Digital and does it affect me?
+
✓

Ready to do this properly?

MerxTax was built specifically for UK self-employed people. MTD compliant, HMRC connected, and simple enough to use in under 5 minutes a week.

Used by self-employed people across the UK · HMRC recognised software