24/7 security coverage calculator

Work out the shifts, hours and guards you need to cover a post, with a relief factor, and pick a shift rotation that fits. Free, no sign-up.

Open the calculator Shift rotations

How many guards do you need for 24/7 coverage?

One post covered 24 hours a day, 7 days a week is 168 hours a week. At 40 hours per guard that is 4.2 full-time guards, so you need at least 5 people to fill the schedule without overtime, plus relief cover for sickness, vacation, training and turnover, which often takes it to 5 or 6. With 12-hour shifts, four teams on a rotation such as 2-2-3 (Pitman) or DuPont cover the post at an average of 42 hours per guard per week.

Calculator

Plan the coverage for a post

Results update as you type. The link in your address bar keeps your figures, so you can bookmark or share it.

Coverage
Shifts and staffing
Extra staff for vacation, sickness, training and turnover.

Your coverage plan

Guards needed with relief
–
Guards to fill the schedule
– at – h/week each
Full-time equivalents (FTE)
–
Hours per week
–
Shifts per week
–
Hours per year
–
How it adds up
Shifts per day, per post–
Whole shifts one guard can work per week–
Relief guards (–)–

This is an estimate for planning. It assumes hours are shared evenly and does not apply overtime, break or rest rules. Check the overtime and working-time rules for your state before you publish a schedule.

Free calculator from ForceVera · forcevera.com/tools/24-7-security-coverage-calculator

Shift rotations

Common shift rotations for security posts

Rotations that use the shift length you chose above are marked. Averages assume one guard per team covering one post.

2-2-3 (Pitman) 12-hour shifts A 14-day cycle of 12-hour shifts: work 2 days, off 2, work 3, off 2, work 2, off 3. Four teams cover a post 24/7. Each guard works every other weekend and averages 42 hours a week, alternating 36-hour and 48-hour weeks, so the long weeks include overtime under a 40-hour weekly rule.
DuPont 12-hour shifts A 28-day cycle of 12-hour shifts with four teams: 4 nights on, 3 off, 3 days on, 1 off, 3 nights on, 3 off, 4 days on, then 7 days off. Averages 42 hours a week and gives a full week off every four weeks, but guards rotate between days and nights.
4 on, 4 off 12-hour shifts Four 12-hour shifts on, then four days off, on an 8-day cycle. Four teams cover a post 24/7 (two on days, two on nights). Averages 42 hours a week; the days worked move through the week, so weekly hours vary.
5 on, 2 off (fixed 8-hour shifts) 8-hour shifts Three 8-hour shifts a day (day, evening, night), each guard working five a week for 40 hours. Covering a post 24/7 takes 21 shifts, or 4.2 guards, so posts usually need a fifth guard who works part time or covers several posts, or a few hours of overtime.
Southern swing 8-hour shifts Four teams rotate through day, evening and night 8-hour shifts over a 28-day cycle, with days off between blocks. Averages 42 hours a week and spreads nights and weekends evenly, but guards change sleep patterns often.
4 on, 3 off (4×10) 10-hour shifts Four 10-hour shifts a week for 40 hours. Suits posts covered up to 10 hours a day, or overlapping shifts where a handover helps. Ten-hour shifts do not divide a 24-hour day evenly, so 24/7 posts usually use 8 or 12-hour shifts.
Method

How the calculation works

  1. Count the hours of coverage

    Multiply the hours covered each day by the days per week and by the number of guards on duty at the same time.

    Weekly hours = hours per day × days per week × guards on duty.

  2. Count the shifts

    Divide each day's coverage by the shift length and round up; the last shift of the day is shorter when it does not divide evenly.

    Shifts per week = ⌈hours per day ÷ shift length⌉ × days × guards on duty.

  3. Work out the full-time equivalents

    Divide the weekly hours by the most hours one guard should work in a week.

    FTE = weekly hours ÷ maximum hours per guard.

  4. Fill the schedule

    A guard can only work whole shifts, so check how many shifts fit in the weekly maximum. The guards needed is the larger of the FTE and the shifts divided by shifts per guard, rounded up.

    Guards = ⌈max(FTE, shifts ÷ ⌊max hours ÷ shift length⌋)⌉.

  5. Add relief

    Add a relief factor for vacation, sickness, training and turnover, and round up.

    Guards with relief = ⌈guards before rounding × (1 + relief %)⌉.

Worked example: one post, 24/7, 12-hour shifts

168 hours a week is 14 shifts of 12 hours. At a 40-hour maximum a guard fits 3 shifts (36 hours), so 14 ÷ 3 = 4.67 rounds up to 5 guards, averaging 33.6 hours each. With 15% relief, 4.67 × 1.15 = 5.37 rounds up to 6. Allow 42 hours a week instead and four guards on a 2-2-3 or DuPont rotation cover the post, with some overtime in the longer weeks.

FAQ

Questions, answered

What is a relief factor?

A relief factor is the extra staff you plan for so a post stays covered when guards are on vacation, sick, in training or leaving. It is usually expressed as a percentage or as guards per post. Work out your own from last year's absences and turnover; this calculator starts at 15%.

What is an FTE in security staffing?

A full-time equivalent (FTE) is one guard working your standard full-time week. A 24/7 post is 168 hours a week, which is 4.2 FTE at 40 hours, or 4 FTE at 42 hours.

Are 8-hour or 12-hour shifts better for 24/7 security?

12-hour shifts cover a day with two handovers and give guards more days off, and four-team rotations like 2-2-3 and DuPont fill a 24/7 post exactly. 8-hour shifts are shorter and less tiring, and avoid daily overtime in states that have it, but they need three handovers a day. Many companies use 12-hour shifts for static posts and 8-hour shifts where alertness or local overtime rules matter.

Do 12-hour rotations cause overtime?

The common 12-hour rotations average 42 hours a week, so under a 40-hour weekly rule some weeks include overtime; in a 2-2-3 pattern the 48-hour weeks have 8 overtime hours. In a state with daily overtime, such as California, hours over 8 in a day are overtime. Use the overtime calculator to estimate it.

Is my data saved?

No. The calculation runs in your browser and your figures are not sent to ForceVera. They are kept only in the page address so you can bookmark or share the plan. The result is an estimate for planning.

Turn the plan into a schedule

In ForceVera you build the week by site and guard, set up recurring and overnight shifts, publish them to the guard app with reminders, and see open posts on the dashboard. See guard scheduling, estimate pay with the overtime calculator, or price the contract with the cost and bid calculator.

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