Contractor vs employee: how the tax differs

Around 4.38 million people worked for themselves in the United Kingdom at the end of the last measured quarter, roughly one in eight of the workforce ^[11]. Whether each of them is taxed as a contractor or as an employee changes the outcome by thousands of pounds a year, because the two statuses run on entirely separate tax machinery ^[1].

An employee is taxed at source through Pay As You Earn, with income tax and National Insurance deducted every payday and an extra employer charge sitting on top ^[3]. A self-employed contractor is taxed after the fact through Self Assessment, pays a different class of National Insurance, and can deduct business expenses that an employee cannot ^[5]. A contractor working through a limited company adds a third layer, dividends, which changes the calculation again ^[6].

Employment status is not a matter of preference. It is decided by the facts of the working relationship, not by the label on the contract, and getting it wrong can leave an engager owing back tax and penalties ^[1]. This guide explains how each status is taxed, what the engaging business pays in each case, and how the off-payroll working rules pull some contractors back onto payroll terms.

The article is written for employers, contractors and payroll administrators who need to understand the tax consequences of each status before an engagement begins.

Key takeaways

• UK tax law splits workers into employees and the self-employed, and the status is set by the facts of the engagement, not by the contract ^[1].
• An employee pays income tax and 8% National Insurance through PAYE, and the employer pays a further 15% employer National Insurance on top for the 2026-27 tax year ^[4].
• A self-employed contractor pays income tax through Self Assessment and Class 4 National Insurance at 6%, with no employer charge and no PAYE deductions ^[5].
• A limited company contractor can draw salary plus dividends, taxed at 10.75% to 39.35%, but the off-payroll working rules can override that treatment ^[6].
• Misclassifying an employee as self-employed exposes the engager to unpaid PAYE, National Insurance and penalties ^[1].

The status that decides the tax

Before any figure can be worked out, the engagement has to be placed in the right category. UK law recognises different statuses for tax and for employment rights, and the two do not always line up ^[2]. For tax, the question is binary: is the worker employed or self-employed on this particular engagement ^[1]?

Employee, worker and self-employed

An employee works under a contract of employment, is integrated into the business, and has the fullest set of statutory rights ^[2]. A worker sits in a middle tier with some rights, such as holiday pay and the minimum wage, but less protection than an employee ^[2]. A self-employed person runs their own business and takes on the commercial risk and reward of it ^[9].

The distinction matters because the same individual can hold different statuses at once. A sole trader might be self-employed for tax purposes while counting as a worker for employment rights on the same job ^[2]. For payroll, only the tax status decides whether deductions run through PAYE or not ^[1].

Why the contract does not settle it

A written agreement that calls someone a contractor carries little weight if the day-to-day reality looks like employment ^[1]. HMRC assesses the substance of the relationship against a set of long-established tests drawn from case law ^[7].

Three factors carry the most weight. Control asks how much say the engager has over how, when and where the work is done. The right of substitution asks whether the worker can send a qualified replacement in their place. Mutuality of obligation asks whether the engager must offer work and the worker must accept it ^[1]. A genuine contractor typically controls their own methods, can substitute, and has no guarantee of ongoing work ^[7].

HMRC provides a free online tool, Check Employment Status for Tax, that runs through these questions and returns its view of the status in around fifteen minutes ^[1]. HMRC stands by the result as long as the answers given are accurate and reflect the real arrangement ^[1]. Any business that regularly engages contractors alongside its own staff on an HMRC-recognised payroll platform should run the check for each engagement rather than assume the label holds.

How an employee is taxed

An employee never handles their own tax on employment income. The employer calculates it, deducts it, and pays it to HMRC every pay period under Real Time Information ^[3]. Three separate charges apply.

Income tax through PAYE

Income tax is deducted at source using the employee's tax code. The standard code, 1257L, gives a tax-free personal allowance of £12,570 for the 2026-27 tax year, after which earnings are taxed in bands ^[3]. The rates for England and Northern Ireland are set out below.

Scotland runs its own bands, with a top rate of 48%, and Scottish codes carry an S prefix ^[3]. Because the deduction happens on every payslip, an employee rarely files a tax return for their salary and cannot defer the liability ^[3].

National Insurance on employment

An employee pays Class 1 National Insurance, deducted alongside income tax. For the 2026-27 tax year, the rate is 8% on earnings between the primary threshold of £12,570 and the upper earnings limit of £50,270, and 2% on everything above that ^[4]. Unlike income tax, National Insurance is calculated on each pay period in isolation rather than cumulatively across the year ^[8].

What the employer pays on top

The cost of an employee does not stop at their salary. The employer pays secondary Class 1 National Insurance at 15% on earnings above the secondary threshold of £5,000 a year, a rate that rose from 13.8% on 6 April 2026 ^[4]. On a £50,000 salary, that employer charge alone is around £6,750 ^[4]. Employers also carry auto-enrolment pension contributions, holiday pay and statutory pay obligations that a contractor does not attract ^[8]. This is the hidden premium that makes employment more expensive to the engager than a headline day rate suggests, and it is why many businesses model the true figure on a UK payroll platform for SMEs before hiring.

How a self-employed contractor is taxed

A self-employed contractor is responsible for their own tax. Nothing is deducted at source: the contractor invoices gross, sets money aside, and settles the bill through Self Assessment after the tax year ends ^[9]. The mechanics differ from PAYE in three important ways.

Income tax through Self Assessment

A contractor pays the same income tax rates and bands as an employee, but on profit rather than turnover, and through an annual return rather than at source ^[9]. Profit is income minus allowable business expenses, so the taxable figure is often lower than the gross fees invoiced ^[10]. Anyone whose self-employed income exceeds £1,000 in a tax year must register for Self Assessment and file a return ^[14].

Because the tax is paid in arrears, a contractor also makes payments on account, two advance instalments towards the next year's bill, which can strain cash flow in the first profitable year ^[14]. An employee never faces this timing pressure, because their tax is already settled each payday ^[3].

Class 2 and Class 4 National Insurance

The self-employed pay different National Insurance from employees, and it is generally lighter. Class 4 National Insurance is charged at 6% on profits between £12,570 and £50,270, and 2% on profits above that, for the 2026-27 tax year ^[5]. Class 2 is no longer a mandatory flat charge: where profits reach the small profits threshold of £7,105, a contractor is treated as having paid it and keeps their contribution record, without handing over any money ^[5]. Below that level, Class 2 can be paid voluntarily at £3.65 a week to protect entitlement to the State Pension ^[5].

The contrast with employment is stark, as the table shows.

The absence of any employer charge is the single biggest structural saving in engaging a contractor, worth up to 15% of earnings above £5,000 to the engaging business ^[4].

Expenses and the business-on-own-account test

A contractor can deduct the costs of running the business before tax is calculated: tools, professional insurance, a proportion of home costs, travel to temporary sites and similar outgoings ^[10]. An employee cannot deduct most everyday work costs in the same way, which is one reason two people on the same headline figure can end up with different tax bills ^[10]. The ability to run genuine business expenses also supports the wider status test, because a person carrying real financial risk looks less like an employee ^[7].

The limited company contractor and IR35

Many contractors work through their own limited company, often called a personal service company. This adds a corporate layer and, with it, a different way of taking money out of the business ^[7].

Salary plus dividends

A company contractor typically pays themselves a modest salary through PAYE and takes the rest as dividends on their shares ^[6]. Dividends are taxed at their own rates, which changed on 6 April 2026, and the first £500 each year is covered by the dividend allowance ^[6].

Dividends carry no National Insurance, which is what makes the salary-plus-dividend mix efficient when it applies genuinely ^[6]. Company profits are also subject to Corporation Tax before dividends can be paid, so the saving is smaller than the headline dividend rates suggest ^[9].

Inside or outside IR35

The off-payroll working rules, known as IR35, exist to stop a worker who behaves like an employee from paying less tax simply by invoicing through a company ^[7]. Where an engagement is judged to be inside IR35, income tax and National Insurance are deducted at source as though the contractor were an employee, wiping out the dividend advantage ^[7].

Since the private-sector reform of April 2021, medium and large clients carry the responsibility for deciding a contractor's status and must issue a Status Determination Statement explaining the decision ^[7]. Smaller clients are exempt, and the size thresholds that define a small company rose on 6 April 2026, with the turnover limit moving from £10.2 million to £15 million ^[7]. Where the small-company exemption applies, the contractor's own company remains responsible for assessing IR35 ^[7]. Businesses that engage a mix of company contractors and payrolled staff can keep both populations compliant through a single payroll bureau software view.

Work out the true cost of each status

Because the employer National Insurance charge, pension and statutory costs only attach to employment, the cheapest option on paper is not always the cheapest in practice once the work is genuinely inside employment terms. Before choosing, an engager can size the employed cost with the Moonworkers UK salary calculator, which applies the 2026-27 PAYE and National Insurance rules to any gross figure.

A quick side-by-side on a £50,000 engagement illustrates the gap. An employee on £50,000 costs the business roughly £56,750 once employer National Insurance is added, before pension and holiday, and takes home pay after 20% tax and 8% National Insurance ^[4]. A genuinely self-employed contractor invoicing £50,000 costs the engager exactly £50,000, pays income tax on profit after expenses, and pays Class 4 National Insurance at 6% rather than 8% ^[5]. The saving to the engager is real, but only where the status is genuine ^[1]. A developer building status logic into an HR or booking platform can automate the payrolled side through the HMRC-recognised payroll API.

Conclusion

The tax gap between a contractor and an employee is not a loophole to be chosen at will. It is the consequence of a genuine difference in how the work is done, and HMRC looks straight through arrangements that dress up employment as self-employment ^[1]. An employee brings certainty and full rights at a higher cost to the engager, driven mainly by the 15% employer National Insurance charge and the statutory obligations that ride alongside it ^[4]. A contractor brings flexibility and a lighter tax profile, but only where the relationship truly carries the risk and independence of running a business ^[7].

The safest position for any engaging business is to decide status on the facts, record the reasoning, and keep the payroll and off-payroll populations cleanly separated. As status rules tighten and thresholds shift, the businesses that treat classification as a documented process rather than a preference will be the ones that avoid an unexpected bill.

Frequently asked questions

Can the same person be an employee for one job and self-employed for another?

Yes. Employment status is assessed engagement by engagement, so an individual can be an employee in one role and genuinely self-employed in another at the same time ^[2]. Each engagement is judged on its own facts using tests such as control, substitution and mutuality of obligation ^[1]. The tax treatment then follows the status of each separate arrangement rather than the person as a whole.

What happens if a business treats an employee as self-employed by mistake?

If HMRC decides that a supposed contractor was really an employee, the engaging business can be liable for the income tax and National Insurance that should have been deducted, plus interest and penalties ^[1]. The liability usually falls on the engager rather than the worker, which is why status should be checked before the work starts. Running the Check Employment Status for Tax tool and keeping the result on file provides a clear audit trail ^[1].

Do contractors pay less National Insurance than employees?

Generally yes, on two counts. A self-employed contractor pays Class 4 National Insurance at 6% on profits rather than the 8% Class 1 rate an employee pays, and there is no employer charge at all ^[5]. An employee, by contrast, triggers a 15% employer National Insurance cost on earnings above £5,000 for the 2026-27 tax year ^[4]. The overall difference explains much of the take-home gap between the two statuses.

How does IR35 change the tax on a limited company contractor?

Where an engagement falls inside the off-payroll working rules, the contractor is taxed broadly as an employee: income tax and National Insurance are deducted at source and the dividend route loses its advantage ^[7]. Where the engagement is outside IR35, the contractor can continue to take a salary-plus-dividend mix through their company ^[6]. For medium and large clients, the responsibility for making that inside-or-outside decision sits with the client, not the contractor ^[7].