The Pay Packet

Employed and self-employed tax calculator 2026/27

A salaried job and a side business are taxed together. Enter both to see your combined 2026/27 tax and National Insurance — and, crucially, what you still need to pay through Self Assessment on top of the tax already taken from your wages.

Your profit is income after expenses.

2026/27. Assumes a standard tax code and no pension.

From £50,000 total income

2026/27
Income Tax (both sources)
£7,486
Class 1 NI — on your salary
£1,794
Class 4 NI — on your profit
£146
Total take-home
£40,574

To pay via Self Assessment

on top of PAYE — Income Tax on profit + Class 4

£3,146

Your job uses part of your tax-free allowance and basic-rate band, so your profit is taxed on top of it.

Verified · 2026/27
21 June 2026
How this was calculated

We add your self-employment profit on top of your salary and apply one Personal Allowance (tapered on the total over £100,000) and the Income Tax bands — so the profit fills the higher bands. Your salary keeps its own Class 1 National Insurance through PAYE; the profit gets Class 4 NI on anything over its own £12,570 limit. The Income Tax on the profit plus that Class 4 NI is what you still owe through Self Assessment. Rates are traced to dated gov.uk sources for 2026/27.

The full method and every source is on our methodology page.

Built & maintained by the Pay Packet team · methodology sourced from HMRC · last reviewed 21 June 2026. About our figures →

Two incomes, one tax position

HMRC does not tax a job and a side business separately — it stacks them. Your self-employment profit sits on top of your salary, so it is taxed at your highest rate. If your job already pays around £45,000, even a small profit can be taxed at 40%, because your wages have used up most of the basic-rate band.

National Insurance is the part most people get wrong. Your wages pay Class 1 through your payslip; your profit pays Class 4 through Self Assessment — and Class 4 has its own £12,570 starting point on the profit. That is why a £40,000 job plus a £6,000 side profit attracts almost no extra National Insurance on the profit: only the slice over £12,570 counts, and there isn’t one.

Because your employer has already collected Income Tax and Class 1 NI on the salary, Self Assessment only needs to collect the rest — the Income Tax on your profit and the Class 4 NI. That is the figure to set aside. For the self-employed side on its own, see the sole trader tax calculator; for the bill and deadlines, the Self Assessment calculator; and for the job alone, the take-home pay calculator.

Employed and self-employed questions

How is tax worked out when I am employed and self-employed?
Your self-employment profit is added on top of your salary. You get one Personal Allowance across both, and the profit is taxed at your highest rate — so if your job already uses up the basic-rate band, your profit can be taxed at 40% from the first pound. Your job’s Income Tax and Class 1 National Insurance are taken through PAYE; the extra Income Tax on the profit, plus Class 4 NI, is paid through Self Assessment.
Why is the Class 4 NI on my profit so low?
Class 4 National Insurance has its own £12,570 starting point applied to your self-employment profit, separate from your job. So a modest side profit can attract very little Class 4 NI even when your salary is high — only the profit above £12,570 is charged, at 6%. (Very high earners with both can hit an annual NI maximum; that rare cap is not modelled here.)
Do I pay National Insurance twice?
No — they are different classes on different income. You pay Class 1 on your wages (through your payslip) and Class 4 on your self-employment profit (through Self Assessment). There is no double charge on the same money.
When do I pay the self-employed part?
Through Self Assessment, by 31 January after the tax year, with payments on account if the bill is £1,000 or more. The tax already taken from your salary through PAYE is credited, so Self Assessment collects only the rest.
Do I need to declare a side hustle?
If your gross income from a side hustle is more than £1,000 in a tax year, yes — you must register for Self Assessment and declare it, even alongside a PAYE job. If it is £1,000 or less, the trading allowance usually means you do not need to tell HMRC at all. The £1,000 is gross income, not profit, so check it before assuming you are under the limit.

An estimate for the 2026/27 tax year — guidance, not personal tax advice, and not a substitute for an accountant or your Self Assessment return. It assumes a standard tax code, no pension and that the rare Class 1/Class 4 NI annual maximum does not apply. Always check the detail with gov.uk/HMRC.