Part-time workers : calculate what you are owed

• A part-time worker is someone who works fewer hours than a comparable full-time worker. GOV.UK says there is no fixed cut-off; full-time is often 35 hours or more a week in practice.
• Statutory paid holiday for almost all workers is 5.6 weeks a year. Part-timers with regular hours for the whole year still get 5.6 weeks, which means fewer days than a five-day full-timer (for example 3 × 5.6 = 16.8 days).
• The Part-time Workers Regulations 2000 ban less favourable treatment on pay, holidays, training, promotion and similar terms just because you are part-time, unless the employer can show objective justification.
• Many benefits (including holiday days and some bonuses) must be applied pro rata. Overtime premiums may wait until you have worked beyond normal full-time hours.
• Under-recorded hours still matter: unpaid opening, closing, handovers or "stay late" minutes can pull your average under the National Minimum Wage. From 1 April 2026, the National Living Wage for workers aged 21 and over is £12.71 an hour (18 to 20: £10.85; under 18 and apprentice rate: £8.00).
• Raise pay and holiday shortfalls with the employer, then Acas. Dual tribunal limits: most claims 3 months minus 1 day as at September 2026; 6 months minus 1 day if the limitation clock starts on or after 1 October 2026.

GOV.UK: a part-time worker works fewer hours than a full-time worker. There is no single statutory number that flips the label. In many workplaces full-time means about 35 hours or more a week. Your written statement, contract and how comparable colleagues work matter more than a job advert slogan.

The Part-time Workers Regulations 2000 define a part-time worker by comparison with a comparable full-time worker: same employer, same type of contract, engaged in the same or broadly similar work, and working or based at the same establishment (with limited fall-backs if no comparator exists there). You do not need a permanent contract to be protected: the Regulations cover workers, not only employees.

Almost all workers (including agency workers, irregular-hours workers and part-year workers) are entitled to 5.6 weeks' paid holiday a year. GOV.UK holiday entitlement is clear that part-time workers who work regular hours for the whole year still get 5.6 weeks, but that entitlement amounts to fewer than 28 days.

GBP / days example: A full-time colleague works 5 days a week and must receive at least 28 days (5 × 5.6). You work 3 days a week on a regular pattern: 3 × 5.6 = 16.8 days of statutory leave. Use the GOV.UK holiday entitlement calculator for odd patterns.

Statutory paid holiday is capped at 28 days. Someone on a six-day week still tops out at 28 days of statutory leave. Employers can offer more leave than the legal minimum; extra contractual leave can have its own rules, but it must not be used to disguise less favourable treatment of part-timers without justification.

Bank holidays do not have to be given as paid leave on top of the 5.6 weeks. An employer can include bank holidays inside statutory annual leave. What they cannot do is give full-timers paid bank holidays as a perk while stripping the same treatment from part-timers without a lawful reason, or shrink your 5.6 weeks below the pro-rata floor.

GOV.UK lists what part-time workers should get the same treatment for:

• pay rates (including sick pay and family leave pay where relevant)
• pension opportunities and benefits
• holidays
• training and career development
• selection for promotion, transfer or redundancy
• opportunities for career breaks

Some benefits are applied pro rata. GOV.UK's Christmas bonus example: if a full-timer gets £1,000 and you work half the hours, you should get £500 unless a different approach is objectively justified.

Overtime: part-timers may not get overtime pay until they have worked beyond the normal hours of a comparable full-time worker. That is a common lawful difference, but it does not authorise unpaid mandatory hours below the NMW floor.

Employers can treat part-timers differently only with objective justification: a good business reason that is proportionate. GOV.UK's health-insurance example is the classic illustration. "We prefer full-timers" is not a reason by itself.

If you think you have been treated less favourably, discuss it with your employer or union first. You can request a written statement of reasons; the employer must reply within 21 days. If you are not satisfied the reason is objectively justified, you may be able to take a claim to an employment tribunal under the Regulations (time limits apply; see below).

Part-time claims and unpaid-hours claims often travel together:

1. Holiday shortfall: leave calculated as if you worked fewer days than your true pattern, or bank holidays handled worse than for full-timers without justification.
2. Under-recorded hours: clock forced off before closing; unpaid team briefings; travel between sites ignored; training squeezed outside paid time.
3. NMW average: pay that counts ÷ hours that count in the pay reference period falls below the legal rate for your age band.

GBP example (pro-rata holiday cash): You are 29 and work 3 regular days a week at £13.00 an hour, 7 hours a day. Daily pay = £91. Statutory leave ≈ 16.8 days. Rough statutory holiday-pay pot at that day rate ≈ 16.8 × £91 = £1,528.80 for the leave year (illustrative; holiday pay for the first 4 weeks should reflect normal remuneration where relevant, and irregular patterns use different methods). If payroll only books 14 days, about 2.8 days are missing ≈ £254.80 before tax treatment.

GBP example (under-recorded hours + NMW): Same worker. Payslip shows 21 hours at £13.00 = £273. You also worked 1.5 unpaid closing hours that week. True hours = 22.5. £273 ÷ 22.5 = £12.13, below £12.71. Floor on 22.5 hours: 22.5 × £12.71 = £285.98. Shortfall ≈ £12.98 that week from the unpaid block alone (rebuild with every pay element that counts for NMW).

Part-time status does not shrink the NMW hourly floor. A lower weekly total is fine; a lower hourly average because hours were truncated is not.

GOV.UK payslips: if pay varies with time worked, the slip must show hours. Compare:

• contracted / usual days
• published rota and amended rota
• clock or timesheet hours
• payslip hours
• holiday balance statements

Keep screenshots of "can you cover Thursday?" messages, till or alarm timestamps, and a simple diary of actual start and finish. For NMW disputes the employer must keep sufficient records and, where you have reasonable grounds, you can request access to your minimum-wage records in writing (they must usually produce them within 14 days). Refusal can itself found a tribunal award of 80 × the hourly NMW rate.

Practical sequence:

1. Write to manager or payroll with dates, hours, holiday days and pound figures.
2. Use the written statement request under the Part-time Workers Regulations if less favourable treatment is the issue.
3. Formal grievance if needed (grievance does not pause tribunal time limits).
4. Notify Acas for Early Conciliation before most tribunal claims.
5. For pure NMW underpayment you generally choose HMRC or a tribunal, not both for the same underpayment.

Dual regime: most unpaid-wages and similar claims use 3 months minus 1 day as at September 2026. From 1 October 2026, most become 6 months minus 1 day if the limitation clock starts on or after that date. A series of underpayments is usually timed from the most recent wrong deduction for presentation purposes, subject to that dual length rule. Part-time less favourable treatment claims under the 2000 Regulations also have their own tribunal time limit (normally three months from the less favourable treatment or the last in a series, with Early Conciliation extension). Check Acas for your claim type.

• "Part-time means half of everything." Holiday is 5.6 weeks pro rata, not a random slice of 28 days invented without the week formula.
• "You are not here on bank holidays so you get nothing." Bank holidays can sit inside the 5.6 weeks, but your pro-rata week entitlement still has to add up; compare how full-timers are treated.
• "Overtime only after 37.5 hours." That can be lawful for premium rates. It does not legitimise unpaid mandatory hours that drag you under NMW.
• "We never had a full-time comparator." The Regulations still define how to find a comparable full-timer; get advice if HR says there is nobody.
• "I'll sort holiday at year-end." Dual tribunal clocks still run from the unpaid payday or treatment date.

Part-time maths is simple once the hours are honest. Paye Mes Heures helps you line up rota days, recorded hours and holiday accrual against the 5.6-week floor and the £12.71 (or youth) NMW rate so you can show payroll a precise gap. Use it to prepare figures, then follow Acas, HMRC or Early Conciliation. It is not a substitute for official advice or a ruling.

• https://www.gov.uk/part-time-worker-rights
• https://www.gov.uk/holiday-entitlement-rights
• https://www.legislation.gov.uk/uksi/2000/1551/contents
• https://www.gov.uk/national-minimum-wage-rates
• https://www.gov.uk/payslips
• https://www.acas.org.uk/if-your-wages-are-not-paid
• https://www.acas.org.uk/employment-tribunal-time-limits