Four-day week trials: what the evidence shows so far in 2026
Trials of a four-day week on full pay have consistently found less burnout and few signs of lost output, and most participating employers keep the model. The evidence is promising but comes mostly from organisations that chose to take part.
Four-day week trials have so far produced consistently positive results for workers and mixed-to-positive results for employers. The largest peer-reviewed study, covering 141 organisations in six countries, found lower burnout and better mental and physical health, and most firms in the best-known trials kept the shorter week afterwards. The main caveat is that the organisations involved volunteered, so they may not represent the wider economy.
What exactly is being tested?
Most trials test a shorter working week on full pay, not the same hours squeezed into four days. The common model is often summarised as 100-80-100: staff keep 100% of their pay, work about 80% of their previous hours and commit to maintaining 100% of their output. Organisations usually redesign work before starting, cutting meetings and low-value tasks.
That is different from a compressed week, where the same hours are worked over four longer days. Some public employers offer a four-day option for other reasons: Tokyo's metropolitan government began offering its staff the option to take three days off each week from April 2025, in an attempt to support young families, NBC News reported. Japan's low birth rate is part of the story we cover in why the world's population is ageing.
What did the UK pilot find?
The UK pilot, run from June to December 2022, was the first large trial and remains the most cited. Of the 61 companies that took part, 56 said they would continue the four-day week and 18 said they planned to make it permanent, NPR reported. Revenue rose by an average of 1.4% over the trial period among the 23 organisations that provided data, absenteeism fell and staff were less likely to quit. The trial was organised by the non-profit 4 Day Week Global, the 4 Day Week Campaign and the think tank Autonomy, with researchers including Boston College's Juliet Schor.
What does the largest scientific study say?
The strongest evidence so far comes from a peer-reviewed study published in Nature Human Behaviour on 21 July 2025. Researchers led by Wen Fan and Juliet Schor of Boston College analysed data from 2,896 employees across 141 organisations in Australia, Canada, Ireland, New Zealand, the UK and the US, before and after six-month trials with no cut in pay.
They found improvements in burnout, job satisfaction, mental health and physical health, a pattern not seen in 12 comparison companies that stayed on a five-day week. Larger individual reductions in hours were associated with greater improvements. Fewer sleep problems, less fatigue and better self-reported ability to work helped explain the gains, which connects with our guide to how much sleep adults need. Because the firms chose to take part and were not randomly assigned, the results may not apply to every employer.
Has the four-day week worked in the public sector?
The best-documented public-sector case is South Cambridgeshire District Council in England, which started a trial for desk-based staff in January 2023. Staff were expected to do all their work in around 80% of their contracted hours on full pay. Independent analysis by the universities of Salford, Bradford and Cambridge found that 21 of 24 services monitored improved or stayed the same, job applications rose by more than 120% and the number of staff leaving fell by more than 40%, the University of Salford said. Councillors voted on 17 July 2025 to make it permanent.
Poland is running the most ambitious government pilot. Its labour ministry received 1,994 applications and selected 90 employers covering more than 5,000 employees, with hours cut by 10% from January to June 2026 and by 20% in the second half of the year, without pay cuts, according to the Polish government. In November 2026, the labour minister, Agnieszka Dziemianowicz-Bąk, said four out of five of the 78 participating employers wanted to continue, Remote Work Europe reported, citing the Polish news agency PAP. Final conclusions are due by May 2027.
| Trial | Scale | Main result |
|---|---|---|
| UK pilot, 2022 | 61 companies | 56 continued, 18 made it permanent |
| Six-country study, published 2025 | 2,896 employees, 141 organisations | Less burnout, better satisfaction and health |
| South Cambridgeshire council, 2023–2025 | Desk-based council staff | 21 of 24 services improved or held steady; made permanent |
| Poland government pilot, 2026 | 90 employers selected, more than 5,000 employees | Four in five employers want to continue (minister, November 2026) |
What are the limits of the evidence?
The results are encouraging but not conclusive, for three main reasons:
- Self-selection. Organisations volunteered for most trials, so they were likely more open to change than average employers.
- Measuring output is hard. Revenue and service indicators are useful, but productivity in many office jobs is difficult to measure precisely, and the UK revenue figure came from only 23 firms.
- Sector fit. Participants were mostly smaller organisations, many of them office-based. Services that run on shifts, such as hospitals or transport, may need extra staff to cover shorter hours.
The debate also runs alongside a separate argument about where people work, which we cover in our explainer on return-to-office mandates.
Frequently asked questions
Does a four-day week mean working longer days?
Not in most trials. The usual model reduces total hours, for example to 32 a week at South Cambridgeshire council, on full pay, while staff aim to keep the same output. A compressed week, where the same hours are squeezed into four longer days, is a different arrangement.
Did productivity fall in four-day week trials?
Available data suggest output was largely maintained. In the 2022 UK pilot, revenue rose by an average of 1.4% among the 23 firms that shared figures. At South Cambridgeshire council, 21 of 24 monitored services improved or held steady. However, measuring productivity in office jobs is difficult, and participating organisations volunteered.
How many companies kept the four-day week after trials?
In the UK's 2022 pilot, 56 of the 61 participating companies said they would continue with a four-day week after the trial ended, and 18 said they would make it permanent. In Poland's 2026 government pilot, the labour minister said in November 2026 that four out of five participating employers wanted to continue.
Which countries are testing a four-day week?
Large trials have taken place in the UK, Ireland, the US, Canada, Australia and New Zealand, many of them run with the non-profit 4 Day Week Global. Poland's government is funding a nationwide pilot in 2026 covering more than 5,000 employees, and Tokyo's city government offers its staff the option of a four-day week.
Sources
- Nature Human Behaviour — Work time reduction via a 4-day workweek finds improvements in workers' well-being (21 July 2025)
- NPR — Dozens of U.K. companies will stick with 4-day workweek (21 February 2023)
- University of Salford — Council votes to permanently adopt four-day week following extensive independent analysis (17 July 2025)
- Polish Ministry of Family, Labour and Social Policy — We have selected participants for the pilot programme (15 October 2025)
- Remote Work Europe — Poland's shorter-working-week pilot: 80% of employers want to keep it (6 November 2026)
- Polskie Radio — Poland picks 90 employers for paid shorter-hours pilot through 2027 (16 October 2025)
- NBC News — Tokyo government to introduce four-day workweek for its employees (9 December 2024)
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