On-Call Time: Definition & Pay Rules

On-call time is any period during which an employee must remain available to the employer outside their normal working hours, ready to perform work if called upon. Whether on-call time counts as working time — and whether it must be paid — depends on the employee’s restrictions, applicable laws, and contractual terms. In the UK, the Working Time Regulations 1998 treat on-call time differently depending on whether the employee must remain at the workplace or is free to spend time as they choose (Gov.uk, Working Time Regulations). In the US, the Fair Labor Standards Act (FLSA) requires payment if the employer “suffers or permits” work, which includes severely restricting an employee’s personal activities during on-call periods (US DOL, Fact Sheet 22).

Understanding the distinction between “at-work” on-call and “away-from-work” on-call is essential for compliance. Getting it wrong exposes you to back-pay claims, overtime disputes, and potential litigation.

Key Takeaways

• On-call time is any period when an employee must remain available for work outside normal hours, but not all on-call time is payable.
• If the employee must stay at or near the workplace, the time is almost always working time and must be paid.
• If the employee is free to go where they choose, on-call time may not count as working time — but restrictions on personal activities can change that.
• The UK’s Working Time Regulations cap average working hours at 48 per week, including on-call time that qualifies as working time.
• Employers must document on-call policies, response expectations, and compensation terms clearly in contracts or handbooks.

What Is On-Call Time?

On-call time covers any arrangement where an employee must remain available outside their scheduled shift or normal working hours to respond to work demands if required. It is distinct from overtime (working additional scheduled hours) and standby time (a less restrictive arrangement in some jurisdictions).

On-call arrangements are common in sectors where service continuity is critical:

• Healthcare — doctors, nurses, and paramedics covering overnight and weekend shifts
• IT and engineering — sysadmins and DevOps engineers responding to production incidents
• Utilities and emergency services — engineers responding to power outages or infrastructure failures
• Hospitality — managers and maintenance staff covering overnight issues
• Legal and financial services — professionals on standby for urgent client matters

The key question in every jurisdiction is the same: does the on-call period count as working time? The answer determines whether you must pay for it.

When Does On-Call Time Count as Working Time?

The UK: Working Time Regulations 1998

Under UK law, on-call time is classified into two categories:

At-premises on-call: If the employee must remain at the workplace (or very close to it), the entire on-call period counts as working time. This is because the employee cannot use the time freely — they are effectively at the employer’s disposal.

Away-from-premises on-call: If the employee is free to go home or spend time as they choose, but must be reachable and able to respond within a specified timeframe, the position is less clear. The Working Time Regulations do not explicitly address away-from-premises on-call, but case law provides guidance:

• If the employee must respond within a very short window (e.g., 15–30 minutes), the restriction on personal freedom may push the time into working time.
• If the employee has reasonable freedom to make personal plans and the response time is more flexible, the time may not count as working time.
• The European Court of Justice ruled in Simpel v Commission européenne (2017) that on-call time where the employee is free to be away from the workplace is not necessarily working time, but each case depends on the specific restrictions.

Key rule: If the employer “controls” the employee’s activities during on-call time, it is working time. If the employee retains genuine freedom, it is not.

The US: Fair Labor Standards Act

Under the FLSA, on-call time is compensable if the employee is “engaged to wait” — meaning the employer controls the employee’s time. Factors that make on-call time compensable include:

• The employee must remain at or near the workplace
• The employee can only respond to calls within a very short window
• The employee cannot use the time for personal activities
• The employer calls the employee frequently during on-call periods

If the employee is “waiting to be engaged” — free to use the time as they choose — the time is generally not compensable.

On-Call Pay Rules by Jurisdiction

Jurisdiction	At-Work On-Call	Away-From-Work On-Call	Minimum Pay	Notes
UK	Working time — must be paid	Depends on restrictions; may not be working time	National Minimum Wage applies to working time	48-hour weekly cap applies
US (Federal)	Compensable working time	Not compensable if employee is free to use time	Federal minimum wage applies to working time	State laws may be stricter
California	Compensable	Compensable if restrictions on personal activities	California minimum wage	24/7 on-call may trigger daily overtime
Germany	Working time — must be paid	May be reduced working time	Minimum wage applies	Collective agreements may set higher rates
Australia	Working time — must be paid	Depends on “on-call allowance” in award	Award rates apply	Modern Awards typically include on-call allowances
Netherlands	Working time	Partially working time if restrictions exist	Minimum wage applies	Sector agreements often define on-call terms

How to Calculate On-Call Pay

UK Calculation

If on-call time counts as working time, you must pay at least the National Minimum Wage (NMW). For workers aged 21 and over in 2025/26, the NMW is £11.44 per hour. If the employee is on-call for 12 hours overnight and receives three calls requiring 2 hours of actual work, the entire 12 hours may count as working time — not just the 2 hours of actual work.

Example:

• Employee on-call from 8 PM to 8 AM (12 hours)
• Two calls requiring 30 minutes of work each
• If classified as working time: 12 hours × £11.44 = £137.28 minimum
• If classified as away-from-premises with genuine freedom: only 1 hour of actual work paid = £11.44

US Calculation

For non-exempt employees, on-call time that counts as working time is paid at the regular rate or overtime rate depending on the total hours worked that week. If an employee works 35 regular hours and is on-call for 10 hours (which counts as working time), they have worked 45 hours — and 5 of those hours are at the overtime rate.

Best Practices for On-Call Policies

1. Document everything — your on-call policy should specify response times, compensation, expectations during on-call periods, and what constitutes an emergency.
2. Keep response times reasonable — a 15-minute response requirement is far more restrictive than a 60-minute requirement and more likely to be classified as working time.
3. Pay fairly — even when the law does not require payment for away-from-premises on-call time, offering an on-call allowance or retainer fee improves morale and retention.
4. Track on-call hours accurately — use time-tracking software to record when on-call periods start and end, and what work was performed during those periods.
5. Review collective agreements — in countries like Germany and Australia, sector-level agreements may impose stricter rules than national law.

Frequently Asked Questions

Is on-call time always paid?

No. Whether on-call time must be paid depends on the level of restriction placed on the employee. In the UK and US, away-from-premises on-call time where the employee retains freedom to use their time may not be classified as working time. However, at-work on-call time — where the employee must remain at or near the workplace — is almost universally classified as working time and must be paid.

What is the difference between on-call and standby?

The terms are sometimes used interchangeably, but in some jurisdictions (including Germany and the Netherlands), standby time is a less restrictive arrangement than on-call. Standby typically means the employee must be reachable but has fewer restrictions on personal activity, while on-call may require a shorter response time and greater readiness.

Can I require employees to be on-call?

You can require on-call availability if it is agreed in the employment contract, a collective agreement, or an applicable award. You cannot impose on-call obligations unilaterally without the employee’s knowledge or consent. In the UK, unreasonable on-call demands could lead to a constructive dismissal claim if the employee resigns as a result.

How does on-call time affect overtime calculations?

If on-call time counts as working time, those hours are added to the employee’s total working hours for the week. In the US, if total hours exceed 40 in a week, the on-call hours contribute to the overtime threshold. In the UK, if total hours (including on-call working time) exceed 48 per week on average, the Working Time Regulations may be breached unless the employee has opted out.

Do I need a written on-call policy?

Yes. A written policy protects both employer and employee. It should define what on-call means at your organisation, the expected response time, compensation terms, what constitutes an emergency, and how on-call hours are tracked. Without a written policy, disputes about expectations and pay are difficult to resolve.