Self-Employed Tax Calculator UK 2026/27: Tax and NI

How self-employed tax is calculated

The figures are for the tax year 6 April 2026 to 5 April 2027. The bill for that year is due by 31 January 2028.

Work out your taxable profit.
Profit = turnover − allowable expenses
Allowable expenses are the running costs of the business, such as office costs, travel, stock, insurance and advertising. For a cost that is partly personal, only the business share counts. If your expenses are under £1,000, the calculator deducts the £1,000 trading allowance in their place.
Work out income tax. Take off the Personal Allowance of £12,570. In England, Wales and Northern Ireland the next £37,700 is taxed at 20%, income above that at 40%, and income over £125,140 at 45%. Choose Scotland to use the Scottish bands. The allowance shrinks once income passes £100,000.
Work out Class 4 National Insurance.
Class 4 = 6% of profit from £12,570 to £50,270 + 2% of profit above
Check the Class 2 position. Nothing is payable for 2026/27. See below for what that means for your State Pension record.
Add it up and plan the payments. The bill is income tax plus Class 4. The calculator divides it by 12 for a monthly amount to put aside, and halves it for each payment on account.

If you also have a job, enter the pay. Your wages use the Personal Allowance and the lower bands first, and the calculator shows only the extra tax caused by your profit.

Worked examples

All three are for England, Wales and Northern Ireland.

A dog walker with £22,000 of profit

No other income. All the taxable profit sits in the basic rate band.

Taxable profit£22,000
Income tax at 20% on £9,430£1,886
Class 4 National Insurance£565.80
Class 2 National Insurance£0
Each payment on account£1,225.90
To set aside each month£204.32
Total to pay£2,451.80

A plumber with £70,000 turnover and £15,000 of expenses

Profit is £55,000, so some of it is taxed at 40% and some Class 4 is charged at the lower 2% rate.

Taxable profit£55,000
Income tax at 20% on £37,700£7,540
Income tax at 40% on £4,730£1,892
Class 4 National Insurance£2,356.60
Class 2 National Insurance£0
Each payment on account£5,894.30
To set aside each month£982.38
Total to pay£11,788.60

An employee on £30,000 with £12,000 of freelance profit

The job has already used the Personal Allowance, so every pound of profit is taxed. Class 4 is nil because the profit is under the Class 4 threshold.

Pay from the job, taxed through PAYE£30,000
Taxable profit£12,000
Income tax at 20% on £12,000£2,400
Class 4 National Insurance£0.00
Class 2 National Insurance£0
Each payment on account£1,200.00
To set aside each month£200.00
Total to pay£2,400.00

Tax and National Insurance by profit

A quick reference for a sole trader with no other income.

Sole trader in England, Wales or Northern Ireland, 2026/27, standard Personal Allowance, no other income.
Profit	Income tax	Class 4 National Insurance	Total to pay	Share of profit	To set aside a month
£15,000	£486	£146	£632	4.2%	£53
£20,000	£1,486	£446	£1,932	9.7%	£161
£25,000	£2,486	£746	£3,232	12.9%	£269
£30,000	£3,486	£1,046	£4,532	15.1%	£378
£35,000	£4,486	£1,346	£5,832	16.7%	£486
£40,000	£5,486	£1,646	£7,132	17.8%	£594
£45,000	£6,486	£1,946	£8,432	18.7%	£703
£50,000	£7,486	£2,246	£9,732	19.5%	£811
£60,000	£11,432	£2,457	£13,889	23.1%	£1,157
£70,000	£15,432	£2,657	£18,089	25.8%	£1,507
£80,000	£19,432	£2,857	£22,289	27.9%	£1,857
£90,000	£23,432	£3,057	£26,489	29.4%	£2,207
£100,000	£27,432	£3,257	£30,689	30.7%	£2,557

The share rises with profit because more of each extra pound falls into higher bands.

Class 2 National Insurance in 2026/27

Class 2 is the contribution that builds a self-employed person's entitlement to the State Pension and some benefits. The position for 2026/27 is:

Profit of £7,105 or more. You do not pay Class 2. Contributions are treated as having been paid, to protect your National Insurance record.
Profit under £7,105. You do not have to pay anything, and you get no credit. You can choose to pay voluntary Class 2 contributions at £3.65 a week, which is about £189.80 for 52 weeks.

That is why the calculator shows Class 2 as £0. Class 4 is different. GOV.UK says Class 4 contributions do not count towards state benefits or the State Pension.

Payments on account

Self Assessment asks for next year's tax in advance. Each payment on account is half of the income tax and Class 4 you owed for the previous year. They are due by midnight on 31 January and 31 July.

Take a profit of £40,000. The 2026/27 bill is £7,131.80. If you made no payments on account for that year, by 31 January 2028 you owe the whole bill plus a first payment on account of £3,565.90, which comes to £10,697.70. Another £3,565.90 is due by 31 July 2028. Those two payments then come off the following year's bill.

You do not make payments on account if either of these is true:

Your last Self Assessment bill was less than £1,000.
More than 80% of the tax you owed was already paid outside Self Assessment, for example through your tax code.

If you expect a lower profit next year, you can ask HMRC to reduce your payments on account, online or with form SA303. If your bill turns out higher than you said, HMRC charges interest on the difference. Student loan repayments and Capital Gains Tax are not part of payments on account. They are settled in the balancing payment each January.

The trading allowance

You can have up to £1,000 of trading income in a tax year tax-free. If your gross trading income is £1,000 or less, you may not need to tell HMRC, though you must keep records. If it is more, you must register for Self Assessment by 5 October after the end of the tax year.

Above £1,000 you have a choice: deduct your real expenses, or deduct the £1,000 allowance. You cannot do both. The calculator uses whichever is larger. You cannot use the allowance against income from a partnership, from your own or a connected person's company, or from your employer.

What the result leaves out

Student loan repayments. If you have a student loan, repayments on your profit are collected through Self Assessment on top of this bill.
Pension contributions. Tax relief on them can lower the income tax due.
Losses. A loss is shown as nil profit. Relief for losses is not worked out.
Other income. Savings interest, dividends and rent are not included, and they can push profit into a higher band.
PAYE that was not exact. The job option assumes your employer collected the right tax on tax code 1257L, and it does not adjust Class 4 for National Insurance you paid through the job.
Partnerships and limited companies. This is for sole traders only.
How you report. Making Tax Digital for Income Tax started on 6 April 2026 for sole traders and landlords whose qualifying income was over £50,000 in the 2024 to 2025 tax year. The calculator works out the tax, not what you have to send HMRC or when.

Common mistakes

Saving a share of profit and forgetting the first January. On £40,000 of profit the first January payment is £10,698, not £7,132.
Working out tax on turnover. Expenses come off first.
Counting your own drawings as an expense. Money you take out of the business for yourself is not an allowable expense.
Assuming Class 4 builds your State Pension. It does not. The Class 2 position does that.
Claiming the trading allowance and expenses together. It is one or the other.

Questions people ask

How much tax do I pay if I am self-employed?

You pay income tax and Class 4 National Insurance on your profit. In 2026/27, a profit of £30,000 means about £4,532 in total, and £50,000 means about £9,732, for a sole trader in England, Wales or Northern Ireland with no other income.

How much should I set aside for tax when self-employed?

It depends on your profit. On £30,000 of profit the bill is 15.11% of profit, about £378 a month. On £50,000 it is 19.46%, about £811 a month. Set aside more in your first year, because payments on account are added.

Do I pay Class 2 National Insurance in 2026/27?

No. If your profit is £7,105 or more, Class 2 contributions are treated as having been paid, which protects your National Insurance record. Below that you pay nothing, but you can choose to pay voluntary Class 2 at £3.65 a week.

What is Class 4 National Insurance?

It is National Insurance on self-employed profit. For 2026/27 it is 6% on profit between £12,570 and £50,270, and 2% on profit above that. It does not count towards the State Pension or other benefits.

What are payments on account?

They are two advance payments towards next year's bill, each half of this year's income tax and Class 4. They are due by 31 January and 31 July. You do not make them if your last bill was under £1,000, or if more than 80% of your tax was paid outside Self Assessment.

Do I pay tax on the first £1,000 I earn from self-employment?

Not if your total trading income for the tax year is £1,000 or less. That is the trading allowance. Above £1,000 you must register for Self Assessment, and you can deduct either the allowance or your real expenses, not both.

Is self-employed tax worked out on turnover or profit?

On profit. Profit is your turnover minus your allowable business expenses. Money you take out of the business for yourself is not an expense.

I have a job and a side business. How is the tax worked out?

Your wages and your profit are added together. The wages use up the Personal Allowance and the lower tax bands first, so the profit is taxed at whatever rate your total income reaches. Class 4 National Insurance is worked out on the profit alone.

When is the self-employed tax bill due?

By midnight on 31 January after the tax year ends. For 2026/27, which ends on 5 April 2027, that is 31 January 2028.

Sources

Figures last checked against these sources on 10 October 2026. This page gives general information and estimates, not tax, legal or financial advice.