Self-Employed Tax on £40,000

Self-employed tax on £40,000 gross income in the 2026-27 tax year: you pay £5,286 in income tax, £0 Class 2 NI, and £1,585.8 Class 4 NI — totalling £6,871.8. Your take-home pay is £2,677.35 per month (£32,128.2 per year).

On a self-employed income of £40,000 in the 2026-27 tax year, your take-home pay is £2,677.35 per month (£617.85 per week). Your total tax bill is £6,871.8, giving you an effective tax rate of 17.6%.

How self-employed tax works

As a sole trader or self-employed person in the UK, you pay three types of tax on your profits:

• Income tax at the same rates as employed workers (20% basic, 40% higher, 45% additional)
• Class 2 National Insurance has no compulsory charge; qualifying profits are treated as paid, and voluntary Class 2 is £3.65 per week
• Class 4 National Insurance at 6% on profits between £12,570 and £50,270, and 2% above £50,270

Unlike employed workers who pay Class 1 NI at 8%, self-employed Class 4 NI is only 6%. However, you don't get employer NI contributions towards your state pension entitlement in the same way.

Expenses and the trading allowance

You can reduce your taxable profit by deducting allowable business expenses -- things like office supplies, travel, insurance, and professional services. Alternatively, if your expenses are low, you can use the £1,000 trading allowance instead. You can claim one or the other, not both.

On gross income of £40,000, your taxable profit is £39,000 (after the £1,000 trading allowance).

Payments on account

HMRC requires most self-employed people to make payments on account -- two advance payments towards your next year's tax bill. Each payment is 50% of your previous year's tax bill.

Based on a £6,871.8 tax bill, your payments on account would be:

• 31 January: £3,435.9 (plus any balancing payment for the previous year)
• 31 July: £3,435.9

This means in your first year of self-employment, you may need to pay up to £13,743.6 (the full year's tax plus the first payment on account). Budget carefully for this.

Self-employed vs employed

If you earned £40,000 as an employee instead, you would pay:

• Income tax: £5,486 (same)
• NI (Class 1): £2,194.4 vs your Class 2 + 4 NI of £1,585.8
• Take-home: £32,319.6 (employed) vs £32,128.2 (self-employed)

As a self-employed person, you pay £608.6 less in National Insurance. However, employees also benefit from employer pension contributions and other workplace benefits. See the full employed take-home breakdown on £40,000.

Frequently asked questions

How much tax do I pay on £40,000 self-employed income?

You pay £5,286 in income tax, £0 Class 2 NI, and £1,585.8 Class 4 NI -- a total of £6,871.8.

When do I need to register as self-employed?

You must register with HMRC by 5 October in your second tax year of self-employment. For example, if you started self-employment in the 2026/27 tax year (after 6 April 2026), you must register by 5 October 2026.

What are the self-assessment deadlines?

• 31 October: Paper tax return deadline
• 31 January: Online tax return deadline and first payment on account
• 31 July: Second payment on account

Do I need to keep records?

Yes. You must keep records of all income and expenses for at least 5 years after the 31 January submission deadline. This includes invoices, bank statements, and receipts.