2025 UK Employment Law Changes

Flexible Working 2 min read

What are compressed hours and how do they work?

Reviewed by Rebecca Hughes, Senior HR Consultant, CIPD Level 7 Last updated: 12 March 2026
Expert Answer

Compressed hours is one of the most popular flexible working arrangements. The employee works their full contractual hours but over fewer days — typically four longer days instead of five standard ones.

Common Compressed Hours Patterns

  • 4-day week — 37.5 hours over Monday to Thursday (roughly 9.5 hours per day)
  • 9-day fortnight — alternating between 5-day and 4-day weeks
  • Annualised hours — longer days during busy periods, shorter days during quieter times

Employer Considerations

  • Working Time Regulations — the 48-hour weekly limit and rest break requirements still apply. Employees must have 11 hours' rest between shifts and a 20-minute break if working more than 6 hours
  • Holiday entitlement — must be recalculated. A 4-day worker gets statutory holiday based on hours, not days (5.6 weeks remains the same)
  • Overtime — clarify whether overtime applies after the compressed day length or after the standard weekly hours
  • Impact on the team — consider coverage, client availability, and meeting schedules
  • Health and wellbeing — longer days can increase fatigue; monitor impact over time

Handling a Request

Compressed hours is a type of flexible working, so requests follow the statutory flexible working process. You must consider the request reasonably and can only refuse on one of the eight statutory grounds.

Trial Periods

Consider offering a trial period (typically 3 months) to assess whether compressed hours work for both the employee and the business before making permanent changes to the employment contract.

Need help managing flexible working requests? Our HR support service can guide you. Get in touch.

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