4-Day Week Results: What the Trials and Job Ad Data Really Show

The 4-day week has been tested in dozens of pilots since 2015, and the results are consistent on one point: when hours are cut without cutting pay, employees report less burnout and better wellbeing, and most companies choose to keep it. What the trials show much less clearly is the effect on productivity and profits, because most were short, self-selected and based on surveys.

This article is the evidence and data guide to the 4-day week: what the main trials in the UK, Iceland, Portugal, Germany, Spain and Belgium actually found, which models exist, where the research is weak and what happens to your pay and hourly rate under each model. It ends with TalentUp data on how many 2026 job ads really offer a 4-day week, and whether those ads pay more or less. If you want the practical how-to, read our guide on implementing a four-day workweek.

What Is a 4-Day Week? The Three Models

“4-day week” is used for three very different deals. Before comparing trial results or job offers, check which one is on the table.

The 100-80-100 formula, popularised by 4 Day Week Global, means 100% of pay for 80% of the time in exchange for keeping 100% of output. That is the model behind most of the headline results below. A compressed week, by contrast, is a scheduling change, not a reduction in working time.

Even advocates stress that the label covers many designs: Joe O’Connor, former CEO of the campaigning organisation 4 Day Week Global and now founder of the advisory firm Work Time Revolution, described how New York PR agency Daly reached a 32-hour week without closing on Fridays.

The Main 4-Day Week Trials and What They Found

UK 2022: The Largest Single-Country Pilot

The UK pilot is the most quoted 4-day week trial. 61 organisations and about 2,900 employees worked reduced hours on full pay from June to December 2022. Firms were free to pick their model: classic Fridays off, staggered days, decentralised or annualised schedules, or a conditional 4-day week linked to targets.

At the end, 56 of 61 (92%) said they would continue and 18 made it permanent. Compared with the same period a year earlier, sick days fell by 65% and the number of staff leaving fell by 57%. 71% of employees reported lower burnout and 39% less stress. Revenue barely moved: +1.4% on average among the 23 organisations that provided figures.

The follow-up report, Making It Stick (February 2024), found that at least 54 of the 61 (89%) still ran the 4-day week a year later and 31 (51%) had made it permanent. The wellbeing gains measured at the end of the pilot were maintained in a survey of staff from 47 organisations.

Iceland 2015–2019: Shorter Weeks, Not Four Days

Iceland is often cited as a 4-day week success, but its trials, run by Reykjavík City Council and the national government, cut the working week from about 40 to 35–36 hours, usually by shortening days. About 2,500 workers took part with no pay cut. According to the Autonomy and Alda analysis, productivity and service provision stayed the same or improved in most workplaces, and wellbeing rose. After the trials, unions negotiated shorter hours, and 86% of Iceland’s workforce now works shorter hours or has the right to.

Portugal 2023: The Government-Backed Pilot

Portugal’s pilot, coordinated by Pedro Gomes (Birkbeck) and Rita Fontinha (Henley Business School), involved 41 companies and more than 1,000 workers, 21 of them starting a coordinated six-month trial in June 2023. Half chose a weekly day off and half a 9-day fortnight. Work time fell by 13.7%, only four companies went back to five days and 80% of managers rated the trial financially neutral. At the interim stage, the share of workers who struggled to balance work and family fell from 46% to 8%, and 85% said they would only move to a five-day employer for a pay rise of more than 20%. Companies that made two or more organisational changes had an 8% chance of reverting, against 38% for those that made one or none.

Germany 2024: The Pilot With Biological Measures

Germany’s pilot started with 45 organisations in early 2024 and was evaluated by the University of Münster. Unlike most trials, it compared participants with control groups inside the same companies and used smartwatches and hair cortisol samples. Four-day-week employees slept about 38 minutes more per week and had fewer measured stress minutes. Turnover and profit rose slightly, but not significantly compared with the previous year, and the small drop in sick days was not significant either. Over 70% of the organisations wanted to continue.

Spain and Belgium: Policy Rather Than Pilots

Spain’s Ministry of Industry set aside €10 million for industrial SMEs that cut full-time working hours by at least 10% for at least 24 months without cutting pay, covering part of the salary cost (up to €150,000) in the first year. The call drew only 42 applications, and in September 2024 just five companies received a total of about €530,000. No evaluation has been published yet.

Belgium took a different path. Since November 2022, full-time workers have the right to request their full-time hours compressed into four days (for example, a 38-hour week worked as four 9.5-hour days), for renewable periods of up to six months. The request must be made in writing, and an employer that refuses must give its reasons. It is a scheduling right, not a reduction in hours.

2025: The First Peer-Reviewed Multi-Country Study

In July 2025, Nature Human Behaviour published a study by Wen Fan, Juliet Schor, Orla Kelly and Guolin Gu covering 2,896 employees in 141 organisations in Australia, Canada, Ireland, New Zealand, the UK and the US. Compared with 12 control companies, employees on a 4-day week reported lower burnout and better job satisfaction, mental health and physical health, and the gains were larger for those whose own hours fell the most. It is the strongest evidence so far, but the authors themselves note that the firms chose to take part.

The Limits of the Evidence

The 4-day week results are encouraging, but they are not the final word. Before using them to argue for or against a policy, keep these limits in mind:

• Self-selection. Companies volunteer for pilots, usually because leadership already believes in the idea and the work can be reorganised. They are not a random sample of employers.
• Short horizons. Most trials last six months. The UK one-year follow-up is encouraging, but long-term effects on careers, promotion and pay growth are unknown.
• Self-reported outcomes. Wellbeing and productivity are mostly measured by surveys of participants who know they are in a trial.
• Few control groups. The UK pilot compared results with the previous year rather than with similar firms. Germany and the 2025 multi-country study used control groups, and their financial results were neutral rather than spectacular.
• Thin financial data. In the UK, only 23 of 61 organisations shared revenue figures.
• Organiser involvement. Several trials were coordinated by 4 Day Week Global, which campaigns for the policy, although the analysis was led by university researchers.
• Sector mix. Pilots are dominated by small, office-based and knowledge-work firms. Shift-based sectors such as hospitals, retail and manufacturing are underrepresented.

In short: the evidence for better wellbeing and retention is strong; the evidence that a 4-day week pays for itself in every sector is not.

What Happens to Pay on a 4-Day Week?

The pay question is where offers differ the most, and where candidates should read the small print.

100-80-100 (full pay, fewer hours). Your monthly salary stays the same while hours fall by about 20%, so your hourly rate rises by 25%. On a €48,000 salary and 40 hours a week, your effective rate goes from about €23 to about €29 per hour. This is the model behind the UK, German and multi-country results.

Compressed hours. You work the same hours in four days, so pay and hourly rate are unchanged. The benefit is the extra day off, not more money per hour. In practice, check how overtime, breaks and public holidays are counted, since a 10-hour day that falls on a holiday can cost you more leave.

4-day part-time (80% pay). Pay is cut pro rata, so your hourly rate is unchanged but your annual income, and usually your pension contributions, fall by about 20%. In the Portuguese pilot, 85% of workers said they would need a pay rise of more than 20% to go back to five days, which helps explain why some people accept this trade.

When comparing offers, convert everything to an hourly rate and total annual package. A “4-day week” at 80% pay is a part-time contract; a “4-day week” at 100% pay with 32 hours is a 25% pay rise per hour. Our guide to benefits in compensation explains how to value non-salary perks alongside base pay.

How Many Job Ads Offer a 4-Day Week? TalentUp Data 2026

Source: TalentUp job postings database, January–September 2026.

Despite the media attention, the 4-day week is still rare in job ads. Between January and September 2026, about 19,000 ads in TalentUp’s global database mentioned a 4-day week or a 9-day fortnight, out of about 22.3 million ads: roughly 8.5 in every 10,000, down from 13.5 in 2024 and 12.1 in 2025 over the same months. The rate is much higher in a handful of markets.

What the data shows:

• Australia is a 9-day fortnight market. About three quarters of Australian mentions are 9-day fortnights, and 83% of all 9-day fortnight ads in our 2026 sample are Australian.
• Austria and the UK lead on the 4-day week itself, with about 50 and 22 mentions per 10,000 ads in 2026. In Austria, the “4-Tage-Woche” is often offered as a scheduling option within collective agreements.
• No sign of a boom. In most large markets the share was lower in 2026 than in 2024, including Germany (28.7 to 14.5 per 10,000) and Spain (6.9 to 2.3). Changes in our sources between years mean the trend is indicative, but nothing in the data suggests the 4-day week is spreading fast through job ads.
• Most ads don’t say what the deal is. In a validated sample of about 1,900 unique 4-day-week ads, 81% don’t specify hours or pay, 9.6% are part-time or pro-rata roles, 7.1% describe compressed hours such as 4 × 10 hours, and only 2.2% explicitly mention full pay or a 32-hour week. 44% present it as possible, optional or on request.
• The roles are not the ones in the pilots. In the US, 63% of 4-day-week ads are healthcare roles, mostly physicians, dentists, nurse practitioners and veterinarians with clinic schedules. In the UK, a third are trades and manufacturing roles such as CNC operators and technicians.

Do 4-Day Week Jobs Pay Less?

Not in a meaningful way. We compared each 4-day-week ad that publishes a salary with the median salary of other ads for the same role in the same country in 2026, excluding part-time and pro-rata ads. The median 4-day-week ad advertises 1.7% less than comparable ads (n = 2,088), with 45% below, 14% about equal and 41% above the comparable median. For 9-day fortnight ads the gap is −0.6% (n = 416).

There are differences by market: in the UK, 4-day-week ads are 1.1% above comparable ads (n = 726), while in the US they are 5.9% below (n = 988). On average, employers do not seem to use the 4-day week as a way to pay less, nor do they pay a premium for it.

Should You Ask for a 4-Day Week? Tips for Candidates

If a shorter week matters to you, the data suggests you will rarely find it advertised, but you can negotiate it. A few practical steps:

1. Clarify the model. Ask whether it is 100-80-100, compressed hours or a 4-day part-time contract. These have very different effects on pay and hours.
2. Compare hourly rates. Divide the annual package by annual hours worked to compare a 4-day offer with a 5-day one.
3. Check what is written in the contract. A 4-day week “as a pilot” or “where business needs allow” can be withdrawn. Ask whether it is in the contract or in a revocable policy.
4. Ask about workload. In the trials, success depended on cutting meetings and low-value work. If the job still has five days of work, the fifth day will come back as overtime.
5. Use your legal rights. In Belgium you can request a compressed 4-day week, and in the UK you can request flexible working from day one. Other countries have rights to request part-time work or flexible schedules.

If you are negotiating more broadly, see our guides on what to do when the salary offered is too low and how candidates judge employers in 2026.

What It Means for Employers

For employers, the 4-day week is a differentiator precisely because it is rare: with fewer than 10 in 10,000 ads mentioning it, an ad that clearly offers a 100-80-100 week stands out. But the trials also show that it only works when the work is redesigned first, and that the pay terms must be stated explicitly, since most ads today leave candidates guessing.

If you are considering it, start with the implementation questions in our four-day workweek guide, review your broader flexible working policies, and compare it with other non-salary levers in what HR can offer besides salary. To check whether your pay stays competitive under any schedule, benchmark your roles with TalentUp’s salary data.

Sources

• TalentUp. Job postings database, January–September 2024, 2025 and 2026: about 19,000 ads mentioning a 4-day week or 9-day fortnight in 2026 (57,000 in 2024 and 40,600 in 2025), a validated random sample of about 2,700 unique ads and 2,088 salary comparisons (see methodology above).
• Autonomy. The results are in: the UK’s four-day week pilot (February 2023).
• University of Cambridge. UK four-day week pilot results (February 2023).
• Autonomy. Making It Stick: The UK Four-Day Week Pilot One Year On (February 2024).
• Fan, W., Schor, J. B., Kelly, O. and Gu, G. (2025). Work time reduction via a 4-day workweek finds improvements in workers’ well-being. Nature Human Behaviour.
• Autonomy and Alda. Going Public: Iceland’s Journey to a Shorter Working Week (July 2021).
• Henley Business School. Portugal’s government-backed 4-day week trial results show drops in anxiety and fatigue (December 2023, interim results).
• Henley Business School. Results from Portugal’s government-backed 4-day week trial released (July 2024, final results).
• University of Münster via idw. Pilot project on the four-day week in Germany (October 2024).
• Ministerio de Industria y Turismo. Press release on the pilot programme to reduce working hours in industrial SMEs (September 2024).
• La Moncloa. Programa piloto de reducción de jornada laboral en pymes industriales (December 2022).
• Ajuntament de València. Jornada semanal de 4 días (March 2023).
• CMS. Belgium implements important changes to employment law in 2022 (2022).