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Freelancer Tax Guide UK 2025: Self-Assessment, Expenses and NICs

Updated July 2025 · 10 min read · By the Factinvo team

Table of Contents

  1. Registering as self-employed
  2. Income Tax and the Personal Allowance
  3. National Insurance Contributions
  4. Allowable expenses for freelancers
  5. Self Assessment: key dates and how to file
  6. Payments on account
  7. Record-keeping requirements
  8. Tax-saving tips for freelancers

Registering as self-employed

If you're freelancing or running a business as a sole trader in the UK, you must register with HMRC as self-employed as soon as you start trading. Technically you must register by 5 October of the second tax year in which you're trading (e.g., if you started in March 2024, register by 5 October 2025).

You can register online at gov.uk/register-for-self-assessment. Once registered, you'll receive a Unique Taxpayer Reference (UTR) — a 10-digit number you'll use for all tax correspondence. Keep this safe.

You must also register for VAT if your annual taxable turnover exceeds £90,000 (see our VAT guide for more detail).

Income Tax and the Personal Allowance

As a freelancer, you pay Income Tax on your profits — that's your income minus allowable expenses — not on your total revenue.

The UK Income Tax bands for the tax year 2025/26 (England, Wales, and Northern Ireland) are:

BandTaxable incomeTax rate
Personal AllowanceUp to £12,5700%
Basic rate£12,571 – £50,27020%
Higher rate£50,271 – £125,14040%
Additional rateOver £125,14045%
Personal Allowance taper: The £12,570 Personal Allowance is reduced by £1 for every £2 of income above £100,000. If you earn over £125,140, you lose the Personal Allowance entirely and pay 40% on all income above £0 (in practical terms, this creates an effective 60% rate on income between £100,000 and £125,140).

Scotland

Scotland has its own Income Tax rates, with six bands. The starter rate (19%) applies from £12,571 to £14,876, then 20% (basic), 21% (intermediate), 42% (higher), 45% (advanced), and 48% (top rate above £125,140). National Insurance rates remain the same across the UK.

National Insurance Contributions

As a self-employed person, you pay two types of NICs:

TypeWhenRate 2025/26
Class 2 NICsIf profits ≥ £12,570/year£3.45/week (flat rate)
Class 4 NICsOn profits between £12,570 and £50,2706%
Class 4 NICs (higher)On profits above £50,2702%
From April 2024: Class 2 NICs are no longer paid separately. If your profits exceed the Small Profits Threshold (£12,570), Class 2 NICs are treated as paid automatically when you file your Self Assessment return, without any additional action required.

Unlike employees who pay Class 1 NICs at 8% (up to £50,270), freelancers pay the lower Class 4 rate of 6% — a saving of 2 percentage points on income up to the higher rate threshold.

Allowable expenses for freelancers

One of the biggest tax advantages of freelancing is being able to deduct business expenses from your income before calculating tax. An expense is allowable if it's incurred "wholly and exclusively" for business purposes.

Office and home working

Technology and software

Travel

Professional services

Marketing and client costs

Training and development

What you CANNOT deduct

Self Assessment: key dates and how to file

As a freelancer, you file a Self Assessment tax return each year to declare your income and expenses. The UK tax year runs from 6 April to 5 April.

5 April
End of the tax year. Your income and expenses for the year are finalised.
5 October
Deadline to register for Self Assessment if you're filing for the first time.
31 October
Deadline for paper Self Assessment returns (very few people use this route).
31 January
Deadline for online Self Assessment returns AND payment of any tax owed. Also the deadline for first payment on account.
31 July
Deadline for second payment on account.

The penalty for missing the 31 January deadline is £100 immediately, plus further daily penalties of £10/day after 3 months (up to £900), plus interest on unpaid tax.

Payments on account

If your tax bill exceeds £1,000, HMRC requires you to make two advance payments toward the following year's tax bill, called payments on account:

This can be a shock in the first year: on 31 January you pay your first year's tax plus the first payment on account for the following year — effectively 150% of one year's tax in one go. Planning for this is essential; many freelancers set aside 25–30% of every invoice payment in a dedicated tax savings account.

Record-keeping requirements

HMRC requires you to keep records of all your income and expenses for at least 5 years after the 31 January submission deadline of the relevant tax year. For the 2024/25 return (due January 2026), you must keep records until at least January 2031.

Good records to keep:

Cloud accounting software makes this much easier. Alternatively, a simple spreadsheet with income and expense columns works well for sole traders with simpler finances.

Tax-saving tips for freelancers

Calculate your take-home pay as a freelancer

Our UK net salary calculator shows Income Tax, NICs, and what you actually keep. Instant results.

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