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Updated Apr 2026

Self-Employed Tax Calculator: 2026/27 UK Tax Year

Estimate your total tax liability, National Insurance contributions, and Take-Home pay. This tool is designed for Sole Traders and Freelancers.

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Estimated Net Profit: £0.00

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Data processed locally. We do not store financial details.

How we calculate your Self-Employed Tax Bill

This calculator connects directly to the UKFinanceTools Tax Engine, using the statutory rates and thresholds provided by HMRC for the 2026/27 tax year. To provide a transparent "Glass Box" figure, we break down the three main deductions that impact your take-home profit.

1. Income Tax & The Personal Allowance

For most UK residents, the Standard Personal Allowance is £12,570. You do not pay any Income Tax on profits up to this amount.

  • Basic Rate (20%): Charged on profits between £12,571 and £50,270.
  • Higher Rate (40%): Charged on profits between £50,271 and £125,140.
  • Additional Rate (45%): Charged on profits above £125,140.

Note: If your total income exceeds £100,000, your Personal Allowance is reduced by £1 for every £2 earned. Our calculator applies this "Taper" automatically.

2. National Insurance (Class 4)

While Class 2 National Insurance has been effectively abolished for most traders, Class 4 NICs remain a significant cost based on your profits.

  • Main Rate (6%): Applied to profits between £12,570 and £50,270.
  • Upper Profits Rate (2%): Applied to any profits above £50,270.

3. Scottish Taxpayers

If you select "Scotland" as your residency, the calculator switches to the Scottish Rate of Income Tax (SRIT). This includes the distinct Starter (19%), Intermediate (21%), and Advanced (45%) bands, alongside the Top Rate.

Do you still pay Class 2 National Insurance?

For most sole traders, no - though it is widely misunderstood. Above £12,570 of profit you pay Class 4 and your State Pension year is credited automatically, with no Class 2 due. Below the small profits threshold (£7,105 for 2026/27) you pay nothing automatically, but you can choose voluntary Class 2 at £3.65 a week to keep that year counting toward your State Pension - usually a bargain.

The payments on account shock

The reason a first self-employed tax bill feels brutal is Advance instalments toward your next Self Assessment bill, due if the bill tops £1,000. Two payments (31 January and 31 July), each 50% of the prior year's tax - so the first January can be about 150% of the tax.. If your Self Assessment bill is over £1,000, and less than 80% of your tax is already collected at source, HMRC asks you to pre-pay next year in two instalments. So your first 31 January can be roughly 150% of the tax: the full bill for the year just gone, plus the first 50% toward next year. The second 50% follows by 31 July.

Why the first January Self Assessment bill is so big The first 31 January is about 150% of the tax: the balancing payment for the year just gone plus the first 50% payment on account. The second 50% follows on 31 July. Why the first 31 January feels brutal 31 Jan This year's tax (100%) +50% on acct = 150% 31 Jul +50% on account this year's tax payment on account
Payments on account mean the first 31 January is about 150% of the tax - the year just gone plus the first instalment toward the next.

It is a cash-flow timing shock, not extra tax - but it catches almost every new sole trader. Our guide to the Self Assessment bill covers how to plan for it.

The £1,000 trading allowance

You can earn up to £1,000 of self-employed income a year before you need to declare it - the A £1,000 tax-free allowance for casual or self-employed income. You can earn up to £1,000 before declaring, or deduct the flat £1,000 instead of your actual expenses - not both.. Above that, you can either deduct your actual expenses or claim the flat £1,000 instead, whichever leaves you better off, but not both.

How much should you set aside?

A safe habit is to move 25% to 30% of every payment into a separate pot for tax and NI, and more once profits reach the higher-rate band. If you are also employed, see employed and self-employed; if you are weighing incorporating, see sole trader vs limited company.

Source: GOV.UK Income Tax Rates & National Insurance Rates

Frequently Asked Questions

When is my Self-Assessment tax bill due?

For online returns, the filing deadline is 31 January following the end of the tax year. You must also pay any tax you owe by this date. If you make Payments on Account, a second payment is due on 31 July.

Why is my first self-employed tax bill so big?

Payments on account. If your bill is over £1,000, HMRC adds an advance payment toward next year, so the first 31 January can be about 150% of the tax - the year just gone plus a 50% instalment. The second 50% is due by 31 July. It is timing, not extra tax.

What are Allowable Expenses?

Allowable expenses are business costs that are not taxable, such as office costs (stationery, phone bills), travel costs (fuel, parking), and financial costs (insurance, bank charges). You deduct these from your turnover to calculate taxable profit. See our full guide to allowable expenses.

Does this calculator include the High Income Child Benefit Charge?

No. This tool focuses on Income Tax and National Insurance. The High Income Child Benefit Charge (HICBC) applies if you or your partner earn over £60,000 and claim Child Benefit, requiring a separate calculation.