Four-day working week: what changes in law?

If you are on your feet in a care home, kitchen, shop or warehouse, a four-day week is not yet a legal right. Your contract still decides your hours and pay. Today, check what your contract says, write down the pattern you want and ask for the change in writing. Do not agree to a pay cut or longer shifts until you know what happens to your pay, holiday and workload.

Two different four-day weeks

First ask whether your weekly hours will change. Then ask about salary. Fewer days do not, by themselves, mean less pay.

The UK trial discussed below used reduced hours on full pay. Employers do not have to offer that deal, but neither does the law require a pay cut when hours fall.

How to ask for one

You can settle a change informally. To use the statutory process, put it in writing. The Acas Code sets out the GB rules.

1. Check eligibility. The statutory route is for employees. Other workers and genuinely self-employed people can ask informally. NI qualifying rules differ.
2. Write a complete request. Date it, call it a statutory flexible-working request, describe the change and start date, and give the dates of previous requests. GB applicants no longer have to explain the business impact.
3. Discuss the proposal. Since 6 April 2024, GB employers must consult before refusing. Ask for a colleague or union representative to attend. Acas recommends allowing a reasonable request, but there is no statutory right to a companion.
4. Track the deadline. The decision, including any appeal, is due within two months of receipt unless you agree an extension. You can make two requests in any 12 months, with only one live at a time.
5. Record the terms. Confirm days, paid hours, breaks, salary, overtime, holiday and start date. Agree any trial’s length and return terms. Otherwise, the change will normally be permanent.

GB employers must handle requests reasonably. The eight permitted refusal grounds concern additional costs, customer demand, inability to reorganise work among existing staff, inability to recruit, harm to quality, harm to performance, insufficient work during proposed hours, or planned structural changes. The current flexible-working tribunal claim examines procedure and incorrect facts, not whether the employer made the best business decision.

Who the rights actually cover

Employees have worker rights too. Someone who is a worker but not an employee has fewer protections. The label “four-day worker” changes neither position.

Agency workers generally have working-time, holiday and minimum-wage rights; SSP depends on eligibility. Genuinely self-employed people gain no employment rights by working four days. A false contractor label cannot remove rights you actually have. See employment status.

Can your employer impose it or cut pay by 20%?

Normally, changing contractual hours or pay needs your agreement. A specific variation clause or collective agreement may affect that position. A general clause is not permission for any change the employer wants. Broad variation clauses benefit employers by shifting the risk of a bad rota onto you.

“Fire and rehire” means dismissal followed by an offer of employment on new terms. It is not automatically unlawful in every case under current GB law, but carries unfair-dismissal risk. Stronger protections are scheduled for March 2027. Collective consultation may also apply to proposed dismissals, not simply to everyone whose rota changes.

An unauthorised pay cut can breach your contract and be an unlawful deduction. That is wage theft. Object in writing and get advice about working under protest. Resigning to claim constructive dismissal is risky. Continuing without objection can weaken your argument that you never accepted the change.

Pay, tax, National Insurance and pension

There is no four-day-week tax break. A 20% gross pay cut need not mean a 20% take-home cut, because deductions usually fall too.

For 2026/27, the standard personal allowance is £12,570. In England, Wales and Northern Ireland, basic-rate tax is 20% on the next £37,700, up to total income of £50,270 with the full allowance. Standard category A employee NI is 8% between thresholds with annual equivalents of £12,570 and £50,270, then 2% above. Scotland’s income-tax bands differ. See HMRC’s rates.

The 2026/27 automatic-enrolment earnings trigger is £10,000; the qualifying-earnings band is £6,240 to £50,270. Earnings are only part of the enrolment test. Check your pension scheme’s contribution basis rather than assuming it uses qualifying earnings.

Your effective hourly pay must meet the applicable minimum wage. From 1 April 2026, the rate is £12.71 for workers aged 21 and over, £10.85 for ages 18 to 20, and £8.00 for under-18s above compulsory school-leaving age. The £8.00 apprentice rate applies to apprentices under 19, or aged 19 and over in their first apprenticeship year. Other apprentices get their age-related rate.

At £12.71, 32 paid hours cost £406.72 a week, or £21,149.44 over 52 weeks. Actual minimum-wage compliance uses the relevant pay reference period; extra hours and certain deductions matter. There is no statutory overtime premium. Agree the rate for your day off. See minimum-wage rights and overtime pay.

Holiday: the bit employers get wrong

For a regular four-day worker employed throughout the leave year, statutory holiday is 5.6 weeks, or 22.4 equal-length working days. Bank holidays can count towards it. They are not automatically days off or extra leave.

At 37.5 hours a week, statutory leave is 210 hours, whether you work five 7.5-hour days or four 9.375-hour days. At 30 hours it is 168 hours. Both four-day patterns give 22.4 days off, but the days are different lengths. Compressed hours must not become a 20% cut in holiday hours.

A Monday bank holiday does not use leave if Monday is not a working day. Check how contractual bank-holiday allowances are allocated. If your pattern changes mid-year, calculate the periods separately.

In GB, legally defined irregular-hours and part-year workers accrue leave at 12.07% of hours worked per pay period for leave years starting on or after 1 April 2024. For 70 hours, 8.449 hours rounds to eight under the nearest-whole-hour rule. Fractions below 30 minutes round down; 30 minutes or more round up.

Rolled-up holiday pay is allowed for those GB categories, not regular-hours staff simply working four days. They must still be able to take leave. For regular-hours workers, regularly paid overtime counts towards normal pay for at least four statutory weeks; the remaining 1.6 weeks can use basic pay. Do not apply these GB reforms automatically in NI. See government guidance and our holiday-pay guide.

Sick pay, family pay, notice and redundancy

Each payment has its own calculation. A shorter week does not mean every entitlement falls by 20%.

From 6 April 2026, SSP is the lower of £123.25 a week or 80% of average weekly earnings, with no lower earnings limit or waiting days. It starts on the first qualifying sick day, subject to eligibility, for up to 28 weeks. Earnings usually use an eight-week average, so a pay cut may not immediately change SSP.

Lower earnings can affect statutory maternity, paternity, adoption and shared parental pay through their reference periods and eligibility tests. Some rates are fixed or capped. GB day-one paternity leave from 6 April 2026 does not mean day-one paternity pay. Ask payroll to calculate the effect before changing hours. See maternity pay and paternity pay.

Lower pay can reduce statutory redundancy pay, subject to its calculation and cap. Notice pay depends on contractual terms and statutory protections, including during absence. Neither should be reduced by a blanket 20% formula. See redundancy pay, notice and SSP.

Part-time workers must not be treated less favourably than comparable full-time workers because they are part-time unless objectively justified. Proportionate benefits are often appropriate; blanket exclusion from bonuses is different. Compressing full-time hours does not automatically make you part-time. See part-time rights.

Does it work? What the trials actually found

The UK pilot ran from June to December 2022 with 61 companies and about 2,900 workers. It retained full pay while reducing time. Afterwards, 56 companies continued. The report recorded a 57% fall in staff leaving and a 1.4% average revenue increase among firms supplying comparable data.

Participants volunteered. These findings are not a representative survey of UK employers, proof of universal benefits or a statutory rollout. The Scottish pilot at South of Scotland Enterprise and the Accountant in Bankruptcy likewise creates no private-sector right. Overseas experiments do not change your UK contract.

The test is whether the fifth day’s work disappears, not whether Friday disappears from the rota.

You might gain a day without commuting or easier childcare. Compressed hours can also mean fatigue and a school pickup you can no longer manage. Reduced hours on lower pay cost money. Full-pay reduced hours avoid that cost, but the job still needs a workable plan.

Agree how workload, customer cover and handovers will change. In a ward, shop or contact centre, someone still needs to cover the fifth day. Staggered days off may work better than closing on Friday. One fewer commute can reduce travel; a particular carbon saving is not guaranteed.

Scotland and Northern Ireland

Scotland shares the core GB employment rules. Different income-tax bands mean Maya’s example is not a Scottish payslip calculation.

In NI, the statutory request normally requires 26 weeks’ continuous employment. You get one request per 12 months, with a staged process, including appeal, of up to 14 weeks. Extensions can be agreed. The same eight refusal grounds apply.

NI’s working-time regulations have the same headline adult 48-hour average limit, 11-hour daily rest and 5.6-week holiday entitlement. April 2026 SSP reforms apply there too. The Employment Rights Act 2025’s flexible-working and fire-and-rehire reforms do not.

The Labour Relations Agency provides NI advice and conciliation, not enforcement. Claims go to NI tribunals. Ordinary unfair-dismissal protection normally needs one year’s service there, compared with two years in GB as at 1 October 2026, subject to exceptions. See nidirect and our NI guide.

If your request is refused

Ask for written reasons. Use an offered appeal to identify wrong facts or suggest alternatives. GB has no statutory appeal right, but Acas recommends one. A grievance or voluntary mediation may also help.

A GB flexible-working claim can challenge statutory-process failures or incorrect facts. The tribunal can order reconsideration and award up to eight weeks’ pay, subject to the weekly-pay cap. It cannot simply award your preferred rota.

A disability-related request also engages the separate reasonable-adjustment duty. Refusal can raise discrimination issues, for example an unjustified hours rule disadvantaging women with caring responsibilities. These are different claims with different remedies.

GB tribunal time limits increased from three to six months on 1 October 2026. The Scottish breach-of-contract change is scheduled for 9 November. Your deadline depends on the event, claim and transitional rules. Normally, notify Acas for early conciliation before claiming; it affects the calculation. A grievance does not stop the clock. Get the deadline checked promptly, especially for pre-October events. NI has separate limits. See our tribunal guide.

Do not face this alone. Ask your union for help: UNISON for care and health, Unite for hospitality, or GMB for retail and logistics. Acas can advise and handle early conciliation; Citizens Advice and local law centres can help you find advice. Report minimum-wage underpayment to HMRC; suspected labour exploitation in covered sectors to the GLAA; unsafe work to the HSE; and discrimination to the EHRC. Early conciliation deadlines keep running, so get advice now, not after an internal grievance ends.

What the Employment Rights Act 2025 actually changes

The Act creates neither a guaranteed four-day week nor a general statutory “right to switch off”. Future dates in the government timetable remain subject to parliamentary processes.

1. 18 Dec 2025Royal Assent

   The Act becomes law, but not every provision starts.

2. 6 Apr 2026In force: SSP and GB family leave

   SSP loses waiting days and the earnings threshold. GB paternity and unpaid parental leave become day-one rights, with separate pay tests.

3. 1 Oct 2026In force: longer GB tribunal limits

   Three months becomes six. The Scottish breach-of-contract change is scheduled for 9 November 2026.

4. 1 Jan 2027Scheduled: unfair dismissal reform

   GB ordinary unfair-dismissal qualification falls to six months for dismissals from this date, with compensatory awards uncapped.

5. Mar 2027Scheduled: fire-and-rehire protection

   Stronger protections against dismissal to force contract changes, moved from the January date.

6. Oct 2027Scheduled: flexible working reform

   Reasonable refusals with explanations. Guaranteed-hours, shift-notice and short-notice payment rights have no confirmed date. None guarantees four days.

Questions people ask

Is a four-day week becoming compulsory?

No. The Employment Rights Act 2025 does not mandate it. A workplace pilot is not a change in law.

Must I take a 20% pay cut?

No. Reduced hours can be agreed on full or proportionate pay. Compressed hours keep weekly hours unchanged. Confirm salary separately.

Do I lose holiday under compressed hours?

You keep 5.6 statutory weeks. Four equal-length days give 22.4 longer days of leave. At 37.5 weekly hours, that is still 210 hours.

Can I try four days and return to five?

Yes, with an agreed trial and return terms. Otherwise, an accepted statutory request normally changes the contract permanently.

Can my employer refuse because Friday needs cover?

Customer demand is a permitted ground. GB employers must consult before refusing. Suggest alternative cover if practical. Discrimination and adjustment duties still apply.

Are Northern Ireland’s request rules the same?

No. Normally, you need 26 weeks’ service, get one request per 12 months and follow a staged process of up to 14 weeks.

Sources

1. Plan to Make Work Pay and Employment Rights Act: timeline update, GOV.UK
2. Employment Rights Act 2025, legislation.gov.uk
3. Employment Rights Act 1996, Part 8A: flexible working, legislation.gov.uk
4. Code of Practice on requests for flexible working, Acas
5. Working Time Regulations 1998, legislation.gov.uk
6. Maximum weekly working hours, GOV.UK
7. Holiday entitlement rights, GOV.UK
8. Holiday pay and entitlement reforms, GOV.UK
9. Rates and thresholds for employers 2026 to 2027, HMRC, including tax, NI, minimum wages and SSP tables
10. Review of the automatic-enrolment earnings trigger and qualifying-earnings band for 2026/27, Department for Work and Pensions
11. Statutory Sick Pay: entitlement, GOV.UK
12. How employment contracts can be changed, GOV.UK
13. Overtime: your rights, GOV.UK
14. Part-time Workers Regulations 2000, legislation.gov.uk
15. Flexible working and work-life balance, nidirect
16. Working Time Regulations (Northern Ireland) 2016, legislation.gov.uk
17. UK four-day-week pilot results, Autonomy and 4 Day Week Global
18. Make Work Pay: consultation on improving access to flexible working, TUC, May 2026
19. Hundreds of employers handed penalties for illegally underpaying workers, Department for Business and Trade / HMRC / Fair Work Agency, 19 March 2026
20. Pay and work rights complaints, GOV.UK
21. Gangmasters and Labour Abuse Authority
22. Contact the Health and Safety Executive
23. Equality and Human Rights Commission