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How many hours can you work before it becomes illegal?
Published 30 June 2026
The demands of work and the constant pull of technology mean many of us are now working more hours than expected - but is there actually a legal limit on how many hours you can work?
Grafting beyond your contracted hours can happen from time to time, or you might even slip into it without noticing until it becomes a habit.
Your working hours are usually set out in your contract of employment, which should also explain whether any extra time you work can be paid as overtime.
When you work more than your contracted hours without extra pay, which many people do, this is known as unpaid overtime.
The Trade Unions Congress (TUC) reported that unions believe strongly that you should be paid for all your overtime, but the practical reality is that for around five million workers each year, this is not the case (1) [Cited 30.6.26]
In 2019, UK workers gave their employers more than £35 billion of free labour. On average, that’s equivalent to having £6,828 taken out of individual pay packets.
Many people do not realise that is actually illegal for your employer to require you to work more than an average of 48 hours per week, unless you voluntarily opt out of that limit.
This rule comes from the Working Time Regulations 1998, which implement the EU Working Time Directive (2) [cited 30.6.26]
But the reality in the workplace can be very different, and that is where this guide will assist you,
How many hours can you legally work?
So you may have heard of the “48‑hour rule,” but many people are unclear on how it actually works and what counts as working time, or when employers cross the line into illegal territory. Here’s the easiest way to explain it.
What the law says
Under the Working Time Regulations 1998, you cannot be required to work more than:
- 48 hours per week on average, normally averaged over 17 weeks.
This means you can work more than 48 hours in a single week, but your average over the reference period must stay below 48.
For employees aged under 18, the rules are much stricter:
- No more than 8 hours a day
- No more than 40 hours a week
When working more than 48 hours is perfectly legal
You can work more hours if you choose to do so, and there are two situations in which this is allowed:
- You voluntarily opt out
You can sign an opt‑out agreement saying you’re happy to work more than 48 hours (3) [Cited 30.6.26] .
Important points:
- It must be voluntary
- You cannot be pressured or punished for refusing
- You can cancel the opt‑out at any time (with up to 3 months’ notice)
- It must be in writing and separate from your main contract
- You work in an exempt job
Some roles are exempt from the 48‑hour limit, including:
- Armed forces
- Emergency services
- Security and surveillance
- Domestic servants in private households
- Seafarers and fishermen
- Senior managers with full control over their hours
Even in these jobs, your employer must still protect your health and safety.
What counts as “working time”?
This can be the confusing bit. This is because working time includes more than just the hours you’re physically doing your job.
According to ACAS, working time includes:
- Travelling to a customer or client, for example if the job is a travelling salesperson.
- Training, if this is needed to do the job.
- Being on call while at the place of work, for example a hotel night manager who needs to be available in case guests need them.
- Doing anything that is treated as working time under arelevant agreement (4) [Cited 30.6.26] .
What doesn’t count?
- Routine travel to and from home and the workplace if you have a set place of work, for example a regular commute to an office or factory.
- Rest breaks when no work is done.
- Training that is not work related, for example a course you have chosen to organise and do for yourself.
This matters because your employer must calculate your average hours correctly. If they don’t, they may be breaking the law.
How the 48‑hour average is calculated
To work out whether you’ve gone over the legal limit, your hours are averaged over a 17‑week period.
You add up all the hours you worked in those 17 weeks, then divide the total by 17.
If the number you end up with is more than 48, and you haven’t signed an opt‑out, your employer is breaking the law.
Can the reference period be longer?
Yes, it can be. If agreed with a union or through a collective agreement it can be up to 52 weeks.
But it is not the same for everyone as some sectors have different rules:
- Junior doctors: 26 weeks
- Offshore workers: 52 weeks
When working too many hours becomes illegal
It becomes illegal when:
- You work more than 48 hours on average without opting out.
If your employer requires this or you are pressured into doing it, then it is breaking the law.
- You’re under 18 and exceed the daily or weekly limit.
If you are not an adult this is a strict rule and no averaging is allowed.
- You’re pressured to opt out
Your employer cannot exert undue pressure, punish, or disadvantage you for refusing.
- Your employer fails to keep proper records.
Employers have to keep records of working hours to demonstrate compliance.
- You’re denied rest breaks.
The law also requires:
- 20‑minute break if working more than 6 hours.
- 11 hours’ rest between shifts.
- 24 hours’ uninterrupted rest each week (or 48 hours every two weeks).
If these aren’t provided, an employer is breaching the Working Time Regulations.
Why these limits exist
The rules may seem like box‑ticking, but they are not and they are in place for very good reasons. They exist to protect people. Limiting working hours is about preventing fatigue, stress, burnout, accidents and long‑term health problems. Employers have a legal duty to safeguard your wellbeing, and once hours become excessive, that duty is undermined.
Common myths
Some general misconceptions
- If I volunteer to work extra, it doesn’t count.
Not true. If your employer expects it, it counts.
- My employer can force me to opt out.”
No, that’s unlawful.
- If I have two jobs, the limit applies separately.”
No, your combined hours must stay under 48 unless you opt out.
- If I’m salaried, the rules don’t apply.”
They do. Salary doesn’t change your rights.
What happens if your employer breaks the law?
If your employer breaks the Working Time Regulations, you’re entitled to take action. You can raise it informally or submit a formal grievance (5) [Cited 30.6.26] . If the matter cannot be resolved with your employer, you can take it to an employment tribunal.
Five FAQs
- Can I opt out and then change my mind?
Yes. You can cancel the opt‑out at any time with suitable notice.
- Can my employer refuse to hire me if I won’t opt out?
No, that would be unlawful.
- Do lunch breaks count as working time?
No, unless you’re required to work through them.
- Does travel time count?
Only if travel is part of your job.
- Can I work 7 days a week?
Only if you still get your weekly rest entitlement.
Finally
Being fully aware of and understanding your rights really is crucial. Long hours can easily feel normal in busy, fast-paced and demanding workplaces, but “normal” doesn’t always mean legal.
Knowing where the limits is vital to help you to protect your health, challenge unsafe practices, push back if demands and expectations go too far, and make well-informed choices about opting out. Perhaps most importantly it will also give you the knowledge and confidence to hold your employer accountable when something is not right.
If you haven’t opted out, your employer cannot require you to work more than an average of 48 hours a week. If they do, they’re breaking the law and you have the right to challenge it.
