12-hour shift rosters for security guards: which pattern to use

A 12-hour shift roster covers a post around the clock with two shifts a day, usually 06:00 to 18:00 and 18:00 to 06:00. It is the usual arrangement in South African guarding, partly because two shifts a day means two handovers instead of three. The pattern you choose decides how many guards the post needs and how many hours each one works in a week.

Which 12-hour shift roster patterns do security companies use?

The pattern is the number of days on followed by the number of days off, repeated. The common ones, with the arithmetic for 12-hour shifts:

• 2 on, 2 off: 24 hours every 4 days, an average of 42 a week and at most 48 in any Monday to Sunday week.
• 4 on, 4 off: 48 hours every 8 days, an average of 42 a week and at most 48 in a week.
• 5 on, 5 off: 60 hours every 10 days, an average of 42 a week and up to 60 in a week.
• 6 on, 3 off: 72 hours every 9 days, an average of 56 a week and up to 72 in a week.

The average is misleading on its own. Four on, four off and five on, five off both average 42 hours, but five on, five off puts 60 hours into some calendar weeks. Six on, three off averages 56 and reaches 72 in some weeks.

How many guards does a 24-hour post need?

A post manned 24 hours a day, 7 days a week needs 168 hours of cover a week. At an average of 42 hours per guard, that is four guards: two crews on days and two on nights, alternating four on and four off.

Four is the minimum. It leaves no room for leave, sickness or a guard who does not arrive, which is why the standby pool matters as much as the roster itself.

What does the law say about 12-hour shifts?

Three sets of rules apply.

The Basic Conditions of Employment Act gives every employee a daily rest period of at least 12 consecutive hours between shifts, and a weekly rest period of at least 36 consecutive hours. A 12-hour roster meets the daily rest by design. The weekly one is where six on, three off can get tight.

The NBCPSS Main Collective Agreement sets pay and hours for the private security sector. Its 2026/27 pricing guide prices a primary security officer's month on four 12-hour shifts a week, which is 48 hours.

Your own employment contracts may average hours over a longer period. Whether a given pattern needs overtime pay depends on what they say, so check the agreement before you pick the pattern, not after payroll. This is not legal advice.

How do you build a 12-hour shift roster in Sentry?

Sentry's guard scheduling has a Pattern scheduler (Schedule, then Pattern scheduler) that builds the roster from the rules rather than shift by shift:

1. Set the minimum number of guards that must be on site.
2. Choose the rotation: 4 on 4 off, 5 on 5 off, 6 on 3 off, 2 on 2 off, weekday day shift, weekday night shift, or your own number of days on and off.
3. Choose the coverage: alternate day and night each cycle, both for 24-hour cover, or day only or night only.
4. Set the day shift times, for example 06:00 to 18:00, and then the night shift times.
5. Choose the period: one month (with the month, year and the day the cycle starts) or a full year.

When the roster is created, one button sends every guard their shifts.

What happens when a guard does not arrive?

In Sentry, guards can be scheduled into a standby pool ahead of time. When a post is short, the supervisor goes to Schedule, then Standby, searches for the site, selects a standby guard and assigns them. The guard gets a WhatsApp and an email telling them which site they have been moved to.

Knowing the gap exists is the other half. Roll-Call on the site handset shows who was expected, who has clocked in and who has not arrived yet.

Where to go from here

Leave is the other thing that breaks a 12-hour roster, because one approved week off leaves a post short on specific nights. We covered that in why leave management is different in the security industry.

If you want to see your own patterns built in Sentry, talk to us.