The 48-hour average working week in Ireland (no UK-style opt-out) : calculate what you are owed

• OTWA section 15 caps average net weekly working time at 48 hours over a reference period.
• For most employees the reference period is 4 months (Workplace Relations Commission and Citizens Information).
• Some sectors or situations use 6 months; a 12-month average needs a collective agreement approved by the Labour Court.
• There is no UK-style individual opt-out in Irish law. A signed waiver is not lawful permission to stay over the average.
• A single week can exceed 48 hours if quieter weeks bring the average back under the limit. The average is what matters.
• Keep your own hour log. Employers must keep working-time records. If the average stays over 48, raise it in writing, then consider a WRC complaint (generally within 6 months of the alleged contravention).

Section 15(1) provides that an employer shall not permit an employee to work, in each period of 7 days, more than an average of 48 hours, calculated over a reference period that does not exceed:

• 4 months in the ordinary case, or
• 6 months in certain activities or where a shorter period would not be practicable for reasons linked to the Act, or
• a longer period (not more than 12 months) specified in a collective agreement approved by the Labour Court under section 24, for seasonal work or where organising work makes a shorter reference period impracticable.

The Workplace Relations Commission (WRC) states the same rule: the maximum average working week is 48 hours, normally over a 4-month period, with averaging over 4, 6, or 12 months depending on the circumstances. Citizens Information adds that a week can exceed 48 hours; it is the average that counts.

“Net” working time here means time you actually work. Periods that do not count toward the average include statutory annual leave (subject to how excess leave is treated), certain family and carer’s leaves, maternity and adoptive leave absences, and sick leave (section 15(4); Citizens Information). Do not pad the average with sick weeks and then claim they “brought you under 48”.

Official anchors:

• OTWA section 15: irishstatutebook.ie
• WRC, Working hours: workplacerelations.ie
• Citizens Information, Working hours: citizensinformation.ie

In the United Kingdom, many employees can sign an individual agreement to opt out of the 48-hour average weekly limit. That mechanism does not exist in Ireland. Irish guidance is clear: employees here cannot opt out of the maximum working week. There is no provision in the OTWA for a personal waiver of section 15.

Why this traps people:

1. Group HR packs written for UK and Ireland often include an “opt-out of the 48-hour week” clause. Relabelling the pack “Ireland” does not rewrite the statute.
2. Managers trained on UK law may say “just sign this and we can roster you freely.” Under Irish law the duty sits on the employer not to permit an excessive average. Your signature does not erase that duty.
3. Senior roles are sometimes outside Part II of the OTWA where the person genuinely determines their own working hours. That is a narrow status question, not a signed opt-out form. If you are on a fixed rota and told when to start and finish, do not assume you are outside the Act.

If you already signed something labelled “opt-out”, keep a copy, but treat the average 48-hour rule as still live unless a solicitor or union adviser confirms a genuine exemption applies to you. For ordinary employees in shops, hospitality, logistics, care, offices, and factories in Ireland, the default is: no individual opt-out.

Citizens Information walks through a standard calculation. Use the same method on your own weeks.

Facts. Your standard week is 40 hours. For the first 10 weeks of a 4-month reference period you also work 12 hours overtime each week. Treat 4 months as about 17 weeks for this illustration (the Citizens Information method).

1. Base hours: 17 × 40 = 680
2. Overtime in the busy block: 10 × 12 = 120
3. Total hours in the reference period: 680 + 120 = 800
4. Average: 800 ÷ 17 ≈ 47.06 hours per week

That average is under 48, so this pattern sits inside the section 15 limit even though several weeks were 52 hours (40 + 12).

Same maths when you go over. Change only the overtime: 15 hours overtime each week for those first 10 weeks.

1. Base: 17 × 40 = 680
2. Overtime: 10 × 15 = 150
3. Total: 830
4. Average: 830 ÷ 17 ≈ 48.82 hours

That average breaches the 48-hour cap. Quieter weeks later in the reference period could still pull the figure down if they arrive in time. Waiting until the period ends before you speak up is risky: by then the breach may already be complete, and the WRC clock for a complaint will be running.

Another check. Contracted 39 hours. Over 17 weeks: 8 weeks at 55, 5 at 45, 4 at 39.

• (8 × 55) + (5 × 45) + (4 × 39) = 821
• 821 ÷ 17 ≈ 48.3 hours average (slightly over)

An employer who “promised” an opt-out form cannot lawfully leave the average above 48. Use real start and finish times. Include overtime and on-call time that counts as working time. Ordinary commuting to a fixed workplace usually does not count (Citizens Information).

If your employer claims a 6- or 12-month period, ask which legal basis they rely on and for a copy of any Labour Court-approved agreement. A verbal “we always average over a year” is not enough.

Night workers have tighter averaging for night work itself (WRC: generally 48 hours per week averaged over 2 months, or longer in an approved collective agreement). That sits beside, not instead of, the weekly average rules that apply to you.

Three issues get tangled:

1. Average hours under OTWA s.15 (health and safety limit).
2. Pay for hours worked under the Payment of Wages Act 1991 and your contract (and any ERO/SEO).
3. National Minimum Wage average hourly rate for a pay reference period.

You can be owed wages for overtime even when the week stayed under 48 hours on average. You can also have a section 15 problem and unpaid hours at the same time. The 48-hour average does not cancel pay rights, and a payslip that “includes everything” does not cure an illegal average.

Employers must keep detailed working-time records (OTWA section 25 and S.I. No. 473/2001). Ask in writing for copies covering the reference period. Keep your own diary, rotas, clock data, and messages asking you to stay late.

Some groups sit outside the usual rules (for example An Garda Síochána, Defence Forces in certain duties, people who genuinely control their own hours). Special regulations cover trainee doctors, mobile road transport, and work at sea. Young workers under 18 have different maxima.

1. Map the reference period. Note whether 4, 6, or 12 months applies. List hours week by week.
2. Raise it internally in writing. Dates, weekly totals, running average, and a clear ask: reduce future hours so the average stays within 48. Keep the email.
3. Ask for statutory records for the same weeks.
4. If nothing changes, consider a complaint to the Workplace Relations Commission about the OTWA breach. The general time limit is 6 months from the alleged contravention, extendable by up to a further 6 months only for reasonable cause. File via workplacerelations.ie.
5. Union or Citizens Information Centre support helps when the employer disputes the reference period or waves a UK-style opt-out.

Do not wait for a quiet season that never arrives. Each week over the average can lock in the breach and shrink your complaint window.

1. “I signed the opt-out, so I’m fine.” Ireland has no individual opt-out. Treat UK-style waivers as a red flag, not a defence.
2. “One 60-hour week is automatically illegal.” Not automatically. The law looks at the average. Still record that week; a string of 60-hour weeks will blow the average.
3. “HR said the Directive lets me opt out.” Irish statute implements the rules through the OTWA. There is no personal opt-out button.
4. Averaging only busy months. Use consecutive weeks in the correct reference period, and exclude leave types the Act says to exclude.
5. Confusing UK forums with Irish ones. Enforcement goes through the WRC (and on appeal often the Labour Court), not ACAS or an Employment Tribunal.
6. Thinking unpaid overtime “doesn’t count” toward the 48. Hours worked count even if missing from the payslip. Unpaid hours are a separate wages claim.
7. Relying on verbal “we’ll rest you later”. Get the plan in writing and check the maths before the reference period closes.

If you are mapping 17 weeks of rotas to see whether you sit under or over 48 on average, Paye Mes Heures (payemesheures.fr) can help you organise dates and hours before you write to your employer or lodge a WRC complaint. It is a preparation aid under Irish working-time rules and your contract, not a substitute for Citizens Information, the WRC, or union or solicitor advice.

1. Organisation of Working Time Act 1997, section 15: https://www.irishstatutebook.ie/eli/1997/act/20/section/15/enacted/en/html
2. Organisation of Working Time Act 1997 (full Act): https://www.irishstatutebook.ie/eli/1997/act/20/enacted/en/html
3. WRC, Working hours: https://www.workplacerelations.ie/en/what_you_should_know/hours-and-wages/working_hours/
4. Citizens Information, Working hours: https://www.citizensinformation.ie/en/employment/employment-rights-and-conditions/hours-of-work/working-hours/
5. S.I. No. 473/2001 (working-time records): https://www.irishstatutebook.ie/eli/2001/si/473/
6. WRC (complaints): https://www.workplacerelations.ie/

General information on Republic of Ireland working-time rules (OTWA, WRC, Citizens Information). Not legal advice. Verify official pages before you act.