Moving from PAYE to invoicing clients changes not only your tax wrappers, but how cash hits your account through the year. This tool keeps the arithmetic explicit so you can negotiate day rates with your eyes open.
What self-employment tax does in the UK
Sole traders pay income tax on profits after the personal allowance and Class 4 National Insurance on bands aligned with income tax thresholds (6% between £12,570 and £50,270, 2% above in the 2025/26 teaching stack used here). Class 2 is a small weekly flat when profits exceed the small profits threshold—budget it as cash even when it looks minor.
Class 2 and Class 4 National Insurance explained
Class 4 rides on your profit figure alongside income tax; Class 2 is separate and visible on your SA statement. Employees split Class 1 with employers—your self-employed headline must replace the employer’s 13.8% NI on PAYE when you compare offers fairly.
Why PAYE and sole trader gross numbers mislead
£65,000 PAYE is not £65,000 Schedule D turnover. Employers pay secondary NI and often subsidies—your day rate must recover that hidden stack plus bench, holidays, and admin time.
Student loans and marginal pressure
Plan 1 / Plan 2 student loans add 9% above thresholds in simplified models—the effective marginal rate can exceed 50% once income tax, NI, and loan coincide.
Pension gap for sole traders
Without employer auto-enrolment, you fund retirement from profit. If you skip it in negotiations, headline net looks higher than sustainable wealth.
Three GBP examples
Teaching illustrations only:
- £40k profit vs £40k salary: employer NI and employee NI differences often leave sole trader cash behind on identical face numbers unless expenses are real. - £65k: basic and higher-rate edges interact; Class 4 at 6% is material across the £12,570–£50,270 band. - £100k: additional rate and 2% Class 4 tail; IR35 risk may push contractors back toward deemed employment—outside IR35 modelling still needs employer-cost parity.
How PAYE quoting differs from your invoice total
Employers operate PAYE at source. You see tax and primary National Insurance withheld before money reaches you. Above the upper earnings limit, NI rates step down—mirroring, imperfectly, how Class 4 works for self-employed profits.
On the freelance path, you must reserve cash for payments on account and student loan, where applicable. Our model approximates your operating profit after common business expenses—layer your own accountant's adjustments for capital allowances and basis periods.
Student loan thresholds: Plan 1, Plan 2, and Plan 5
Plan thresholds interact with your earned or trading income. At common tech salaries, an extra £1 of profit can trigger nine pence of student loan alongside income tax and NI—an effective marginal rate that surprises people who only looked at headline income tax bands.
Pension auto-enrolment
We assume a typical employee contribution for illustration and show employer pension as part of total reward. You can adjust figures to mirror your scheme. Drawdown, annual allowance, and tapered protections are outside the scope of this simple sheet.
Important
Indicative only — not tax or legal advice.
Common mistakes when comparing UK net pay
Comparing gross to gross without the employer-NI stack
A £65,000 self-employed profit is not the same negotiating unit as £65,000 on a payroll line. Employers pay secondary National Insurance (~13.8%) above the secondary threshold and fund auto-enrolment—costs that rarely appear on your payslip. If you ignore that loaded cost, PAYE looks artificially “cheap” and freelance looks artificially “expensive” for the same lifestyle target.
Forgetting the Class 2 flat charge
Class 2 is small (£3.45/week, about £179/year in 2025/26) but it is real cash on top of Class 4 and income tax, and it feeds into payments on account. Models that only colour in Class 4 subtly overstate sole-trader take-home.
Ignoring the pension gap
Employees get auto-enrolment and often meaningful employer matching. Sole traders must consciously fund SIPP or other wrappers from profit, not from a silent payroll line. If you compare nets while the employee column carries 5% salary sacrifice and the freelance column carries £0, you are not comparing two sustainable lifestyles.
Assuming 52 billable weeks
52 fully billable weeks is rare once you book holiday, training, admin, sick days, and business development. 44–46 effective weeks is a more honest planning range for many independents—your turnover target needs to survive that slack, not just the headline day rate.
Worked examples — three GBP income levels
| Row | £40k equivalent | £65k equivalent | £100k equivalent |
|---|---|---|---|
| Gross income (PAYE salary / sole trader profit) | £40,000 | £65,000 | £100,000 |
| Income tax (sole trader) | £5,486 | £13,432 | £27,432 |
| Class 4 National Insurance | £1,646 | £2,557 | £3,257 |
| Class 2 National Insurance | £179 | £179 | £179 |
| Estimated net (PAYE) | £30,720 | £46,307 | £65,557 |
| Estimated net (self-employed) | £32,689 | £48,832 | £69,132 |
| Net difference (self-employed − PAYE) | +£1,969 (+6.4%) | +£2,525 (+5.5%) | +£3,575 (+5.5%) |
Indicative only — actual figures depend on expenses, pension contributions, and student loan plan. Built from 2025/26 UK bands in this tool (personal allowance £12,570; employee NI 8%/2%; Class 4 6%/2%); PAYE net includes 5% employee pension—freelance column has no SIPP in this snapshot.
Self-employment across UK regions
Income tax for most England, Wales, and Northern Ireland taxpayers follows the UK-wide bands modelled in this tool. Scotland sets its own Scottish Rate of Income Tax bands: in 2025/26 teaching terms you will see starter 19%, basic 20%, intermediate 21%, and higher 42% on slices that do not line up one-for-one with rUK—so an identical £ profit can carry a different effective rate north of the border.
Wales uses the same rates and thresholds as England for these purposes. Northern Ireland also follows the same regime as England for income tax. This calculator therefore uses England/Wales-style bands; if you are resident in Scotland, treat the output as a baseline and allow roughly 1–2 percentage points of extra effective rate at common middle incomes until you model the Scottish schedule explicitly with your accountant.
Who benefits most from self-employment in the UK?
When sole trader tends to win
Self-employment works when:
- Your **day rate** clears market floors for your skill once **employer NI** is added back.
- You claim **legitimate expenses** (travel, software, professional subscriptions).
- You maintain **utilisation** and low **bad debt**.
When PAYE is smarter
Prefer employment when:
- **Benefits** (employer pension, insurance, stock) are large versus your freelance premium.
- You are **IR35-caught** or need **paid leave** stability.
- Student loan and marginal rates wipe out small rate uplifts.
FAQ
You pay income tax on taxable profit after allowances and Class 4 NI on most trading profits, plus Class 2 where applicable; effective % rises with bands and student loans.
This page pairs our PAYE vs sole trader engine with UK bands so you can see net cash side by side under simplified 2025/26 assumptions.
Not automatically, but without employer NI sharing you often need higher gross turnover to match PAYE net; Class 4 replaces part of that story for profits.
Start from revenue minus allowable expenses, apply income tax bands, add Class 4 and Class 2 NI, then subtract student loan in the tool if relevant.
A self-employed person earning £65,000 in 2025/26 pays roughly £15,430 in income tax (20%/40% split at £50,270), plus £3,599 Class 4 NI (6% between £12,570–£50,270, 2% above), plus £179 Class 2 NI — leaving approximately £45,790 net before pension and expenses. Compare with PAYE net using the calculator above.
Not automatically. At the same gross income, self-employed net is often slightly lower than PAYE net once you account for Class 2 and Class 4 NI, plus the absence of employer pension contributions. The self-employed advantage comes from deductible expenses — not from lower tax rates. The calculator above shows the real gap for your specific income level.