What Counts As Part-Time Work In The UK?

If you’re hiring in the UK, “part-time” can feel like a simple label - until you need to put it into a contract, work out holiday entitlements, or explain working hours to payroll.

And that’s where most small businesses get stuck: what is considered part-time work in the UK, legally and practically?

The good news is you don’t need to overcomplicate it. But you do need to understand how part-time status affects your obligations around pay, working time, holidays, and equal treatment - so you stay compliant and protected from day one.

What Is Considered Part-Time In The UK?

There isn’t one fixed number of hours in UK law that automatically makes someone “part-time”. In other words, the legal system doesn’t say “under X hours = part-time”.

Instead, in most workplaces, what is considered part-time is judged relative to your business’s normal full-time hours.

The Practical Definition Most Employers Use

As an employer, you’ll usually treat someone as part-time if they work:

• fewer hours than your comparable full-time staff (for example, 16 hours/week where full-time is 40), and
• on a regular pattern (for example, 3 days a week, mornings only, or term-time).

In many industries, full-time is commonly around 35–40 hours per week, which is why you’ll sometimes see “under 35 hours” described as part-time. But that’s convention, not a legal threshold.

Why “Relative To Full-Time” Matters

Part-time status becomes important because of how the law protects part-time workers from being treated worse than comparable full-timers doing similar work.

That’s mainly covered by the Part-time Workers (Prevention of Less Favourable Treatment) Regulations 2000. In plain English: if you have someone working part-time, you should generally offer them the same overall “package” as full-time staff - but pro-rated where appropriate.

So, if you’re asking what is considered part-time because you want to reduce benefits or holiday, it’s worth pausing. This is exactly where legal risk can creep in (often unintentionally).

Why Part-Time Status Matters For Employers (Beyond The Label)

For small businesses, the main issue isn’t what you call the role - it’s whether your hours, pay, and policies line up with UK employment rules.

Part-time status can affect:

• holiday entitlement (usually pro-rated)
• pay and minimum wage compliance (still applies, even for short shifts)
• rest breaks and working time limits
• overtime expectations and how you calculate it
• access to benefits (pension auto-enrolment, bonuses, commission structures)
• redundancy selection risk (part-time employees shouldn’t be unfairly targeted)

Even if you’re offering “just a few shifts”, it’s still smart to document the arrangement properly in an Employment Contract so everyone is clear on expectations.

Key Legal Rules You Need To Follow For Part-Time Staff

Once you’ve decided that a role is part-time (or you’re hiring someone for fewer hours than full-time), the next step is understanding the legal rules that sit behind it.

1) Equal Treatment For Part-Time Workers

Under the Part-time Workers Regulations, part-time staff should not be treated less favourably than comparable full-time employees without objective justification.

This often comes up with:

• bonus eligibility
• training access
• promotion opportunities
• enhanced sick pay schemes
• company perks (for example, gym memberships or private healthcare)

Some benefits can be pro-rated (and many should be), but excluding part-time workers altogether can be risky unless you’ve got a clear, defensible reason.

2) Working Time Rules Still Apply

Part-time doesn’t mean “outside the rules”. Your part-time employees are still covered by the Working Time Regulations 1998 - including rest breaks, daily/weekly rest, and holiday.

If you’re setting shift patterns or asking staff to pick up extra hours at short notice, it helps to understand the boundaries in the Working Time Regulations and how they apply in practice.

3) Holiday Entitlement (Usually Pro-Rated)

Most workers are entitled to 5.6 weeks’ paid holiday per year. For part-time employees, you usually calculate this on a pro-rata basis based on their working pattern.

For example:

• If full-time staff work 5 days/week and get 28 days’ leave (which may or may not include bank holidays depending on your policy),
• and your part-time employee works 3 days/week,
• then their holiday would typically be 3/5 of 28 = 16.8 days.

In practice, you’ll also need a consistent approach to rounding and booking leave (for example, whether you allow half days or hours, and how your payroll/HR system records leave). Holiday admin is one of those areas that seems small - until a dispute, resignation, or tribunal claim forces you to reconstruct what happened.

4) Overtime, Extra Hours, And “Part-Time Plus” Arrangements

A common small business scenario is a part-time employee regularly working beyond their contracted hours - for example, they’re contracted to 20 hours but often work 30.

That can be fine, but you should be clear on:

• when additional hours are “optional” versus expected
• the rate of pay for additional hours (standard rate or overtime rate)
• how much notice you’ll give for extra shifts
• whether regular extra hours mean you should formally amend the contract

This is where having a clear approach to overtime rules can save you a lot of headaches later, especially if the employee later argues their “real” hours were higher than stated.

How To Set Part-Time Hours In A Way That Works For Your Business

When you’re deciding what is considered part-time for your team, you’re really making a business decision about coverage, cost, and flexibility.

Here are a few common part-time patterns small businesses use (and what to watch for).

Fixed Weekly Hours (Most Straightforward)

This is usually the cleanest setup: for example, Monday to Wednesday, 9am–5pm, every week.

Pros:

• Simple payroll and holiday calculations
• Predictable staffing and rota planning
• Clear expectations and fewer disputes

Tip: Put the working days/hours in the contract (and make sure any flexibility clause is fair and realistic).

Part-Time Shift Work (Retail, Hospitality, Care, Trades)

If your staffing is rota-based, a part-time employee might have variable shifts each week but still be “part-time” overall (because they work fewer hours than full-time staff).

In this model, it’s important to document:

• how rotas are issued (how much notice)
• the employee’s availability requirements
• any guaranteed minimum hours
• how you handle shift swaps and cancellations

If there are no guaranteed hours and the individual is offered work only as needed, you may be looking at a more casual arrangement such as a zero-hours structure. If that’s the case, make sure you’re comfortable with the operational and legal implications - including notice expectations - for example, how notice on a zero-hour contract may work in practice.

Term-Time Or Seasonal Part-Time

Some businesses hire part-time staff for term-time only, peak season only, or to cover specific events.

This can be a great fit - but consider whether a fixed-term contract is more appropriate, and ensure holiday is handled correctly (often accrued). If you’re unsure, it’s worth getting tailored advice before you commit to a structure that doesn’t match what’s actually happening day-to-day.

What Should You Put In A Part-Time Employment Contract?

If you want to keep things smooth (and reduce the risk of disputes), your part-time arrangements should be documented in writing. It’s not just “nice to have” - it’s good business hygiene.

At a minimum, your part-time contract should clearly set out:

• job title and core duties
• place of work (including any mobility expectations)
• working hours (and whether they’re fixed or variable)
• pay (hourly rate or salary) and pay frequency
• overtime/additional hours rules
• holiday entitlement and how it’s calculated for part-time hours
• sick leave and sick pay approach
• probation period (if applicable)
• notice periods for termination (by both sides)
• confidentiality and basic conduct expectations

Probation is particularly useful for small businesses hiring their first team members, because it creates a structured review point early on. If you use probation, be clear and consistent with it - your Probation Period clause should match how you actually manage performance.

In many cases, you’ll also want to include policies (or refer to a staff handbook) covering things like flexible working requests, sickness reporting, and disciplinary/grievance procedures.

Be Careful With “Flexibility” Clauses

It’s normal to want flexibility in a part-time role - especially if your workload changes week to week. But vague clauses like “hours may change at any time” can backfire.

Why? Because they can lead to disputes about:

• whether additional hours were truly optional
• whether the employee had agreed to a change
• what the “real” contracted hours are

A better approach is to define a baseline (for example, 20 hours per week) and explain how extra hours are offered and agreed.

Common Questions Small Businesses Ask About Part-Time Work

Even once you understand the “relative to full-time” concept, you’ll likely have some practical questions when running your team day to day.

Can You Have A Part-Time Employee On A Salary?

Yes. Part-time employees can be salaried, as long as the salary is appropriate for their agreed hours and still meets National Minimum Wage requirements based on hours worked.

Be very clear in the contract about:

• the expected hours (weekly or monthly)
• how you handle additional hours
• whether the salary includes any overtime or not

Can Part-Time Employees Work More Hours Some Weeks?

Yes, but regular “temporary” extra hours can quietly turn into the norm.

If someone consistently works more than their contracted hours, consider whether you should:

• update their contract to reflect reality, or
• adjust how you staff shifts so you don’t rely on informal overtime.

Do Part-Time Employees Have The Same Rights As Full-Time Employees?

Often, yes - just pro-rated where appropriate.

Part-time staff are generally protected under the same key employment laws (for example, protection against discrimination under the Equality Act 2010) and should not be treated worse simply because they work fewer hours.

Is “Part-Time” The Same As “Worker” Or “Employee” Status?

No - and this is an easy trap.

Part-time describes working hours. Employment status (employee vs worker vs self-employed contractor) describes the legal relationship.

You can have:

• a part-time employee (most common)
• a part-time worker (for example, casual staff with fewer mutual obligations)
• a part-time contractor (but they’re not “part-time” in the employment law sense - they’re just providing services for fewer hours)

If you’re not sure which category your hire fits into, it’s worth getting advice early - misclassifying staff can create knock-on issues for rights and entitlements (and, separately, tax and payroll treatment).

Key Takeaways

• There’s no single legal number of hours that defines part-time work - what is considered part-time is usually based on whether the person works fewer hours than your comparable full-time staff.
• Part-time staff are protected against less favourable treatment under the Part-time Workers Regulations, meaning benefits and opportunities should generally be the same as full-time roles (often pro-rated).
• Working time and holiday rules still apply to part-time workers, including rest breaks and paid holiday (usually calculated pro-rata).
• Be clear about additional hours and overtime, especially where part-time employees regularly work beyond their contracted hours.
• A written contract is essential for setting expectations around hours, pay, flexibility, holiday, and notice - particularly for rota-based part-time roles.
• “Part-time” is about hours, not status - make sure you’re also clear whether someone is an employee, worker, or contractor.

Note: This article is general information for employers and isn’t tax advice. If you need help hiring part-time staff, reviewing your working hours setup, or putting the right contracts in place, you can reach us at 08081347754 or team@sprintlaw.co.uk for a free, no-obligations chat.