Most security quotations answer a question the buyer has not asked. The buyer wants to know how many guards their site requires; the quotation states how many guards the agency proposes to supply. Those are different things, and the difference is invisible until something is uncovered or the invoice looks higher than expected.
This article sets out a method for arriving at a defensible number before any agency is approached. It produces a posting plan rather than a headcount, which is what makes a quotation comparable with another quotation, and what allows a buyer to recognise both over-manning and under-manning.
The method has four steps: establish the posts, establish the hours each post must be covered, convert covered hours into people, and then test the result against the site’s actual risk.
Step 1: Establish the posts
A post is a position that must be occupied, not a person. Begin by listing every position the site requires someone to be at, independent of how many people that will eventually take.
For most commercial and residential sites the list is drawn from the following. Include only those that genuinely apply.
- Main gate — one post per vehicular gate in use.
- Pedestrian gate — where it is separate from the vehicular gate and is used.
- Reception or lobby — where visitors are received inside the building.
- Basement or parking — where parking is extensive, multi-level, or has its own entry.
- Patrol — a roving position rather than a fixed one, covering floors, perimeter and common areas.
- Material or service gate — where goods movement is separated from the main entry.
- Specific fixed posts — a server room, a cash area, a store, a site-specific requirement.
- Supervision — on larger sites, a shift supervisor who is not counted within the posts above.
The common error at this step is to merge posts that cannot in practice be merged. A single guard cannot simultaneously hold the gate and patrol the building; a guard who leaves the gate to investigate the fourth floor has vacated the gate. If the site requires both at the same time, that is two posts, and no arrangement of the duty chart will make it one.
Step 2: Establish the covered hours for each post
For each post, decide the hours during which it must be occupied. Not every post needs round-the-clock cover, and assuming it does is the most common source of over-quoting.
| Cover pattern | Hours per week | Typically applies to |
|---|---|---|
| Round the clock, all week | 168 | Main gate at a residential or 24-hour site |
| Day only, all week | 84 | Reception at a residential project |
| Business hours, six days | ~72 | Office reception, visitor management |
| Night only, all week | 84 | Patrol at a site that is closed at night |
| Peak hours only | varies | Second gate position during entry and exit surges |
The “peak hours only” row matters more than its placement suggests. Many sites do not need a second guard at the gate for sixteen hours; they need one for the three hours in which entry volume exceeds what one person can process. Identifying that window precisely is often the difference between a workable plan and an unaffordable one.
To identify it, count. Stand at the gate for a week and record entries per half hour, separating pedestrians from vehicles. The shape of that distribution will usually make the decision obvious.
Step 3: Convert covered hours into people
This is the step at which most informal estimates go wrong, and the error is always in the same direction.
A post that must be occupied 24 hours a day, seven days a week, requires 168 hours of cover every week. A single person does not provide 168 hours. They provide a lawful duty pattern, with a weekly day off, and they are at some point on leave or absent. Covering 168 hours therefore takes meaningfully more than three people, once the weekly off and absence cover are provided for honestly.
The practical consequence is this: when comparing two quotations for the same 24-hour post, the one proposing fewer people is not more efficient. It is either absorbing the gap, or the post will be uncovered for part of the week and billed as though it were not.
For planning purposes, work in covered hours rather than in people, and let the agency convert. Then ask each agency to show the conversion. A quotation that cannot explain how its headcount delivers the stated cover has not been built from the site’s requirement.
Step 4: Test the result against the site
The arithmetic produces a number. The following questions test whether that number is the right one, and they are where a site assessment earns its value.
Can the gate post see what it must control? If the gate cannot observe the pedestrian entry, that is a second post or a physical change, not an instruction.
What is the longest the site is without a patrol? Walk the interval. If a loss occurring just after a round would not be discovered for three hours, decide whether that is acceptable, and if not, change the frequency rather than the headcount.
Where does the plan assume someone can be in two places? Read the duty chart looking specifically for a guard expected to hold a position and perform a task elsewhere. This is the most common defect in a posting plan and it is always visible on paper.
What happens at shift change? Handover takes time and both guards are occupied during it. If the shift change coincides with a peak, the site is at its thinnest exactly when it is busiest.
Which posts are genuinely necessary, and which are habitual? Sites accumulate posts. A position created for a construction phase that ended two years ago is still being billed at some sites, and removing it funds a genuine requirement elsewhere.
What legitimately changes the number
Two sites of identical size can require quite different cover. The factors below are the ones that genuinely move the requirement, as distinct from those that are often cited but do not.
Number of entry points in use. The strongest single driver. Each gate that is open is a post. The cheapest security decision available to most sites is to close a gate that exists for convenience rather than necessity, and route that traffic through a controlled one.
Entry volume at peak, not average. A site processing 400 entries spread across the day needs less than one processing 300 of them within ninety minutes. Plan to the peak, because that is when control fails.
Separation of goods from people. Where material movement shares the main gate, that gate needs capacity for both, and in practice the goods traffic displaces the people control. A separate service gate often reduces total cover rather than increasing it.
Line of sight. A gate from which the guard can observe the pedestrian entry, the visitor parking and the approach does the work of two posts. One from which they can see none of those does not. This is why a physical survey precedes the arithmetic.
Hours of genuine activity. A building that empties at eight does not need the same posture at two in the morning as one running a night shift. Matching the pattern to actual occupancy is usually where an over-specified plan is corrected.
Factors that are commonly cited but do not by themselves determine the number include total built-up area, the number of flats or seats, and the value of assets held. Each may raise the consequence of a failure, and so justify a tighter standard at a given post, but none tells you how many positions must be occupied.
Supervision is a separate line
Supervision should be planned and costed separately from the posts, not absorbed into them. A supervisor who is also holding a post is not supervising; they are occupying a position and answering a phone.
The question to settle is how often a supervisor physically attends the site, at what hours, and what they verify when they do. Night visits matter disproportionately, because that is the period with no other oversight. The visit should leave a record the client can inspect.
This is the line most often reduced quietly when an agency is under margin pressure, precisely because the client cannot see it from the gate. Specifying it in the posting plan, and asking for the visit log monthly, is what keeps it real.
A worked example
Consider a commercial office building: one vehicular gate, a separate pedestrian entry, a reception inside the lobby, two basement parking levels, and a requirement for floor patrolling during working hours.
- Main gate — round the clock, all week.
- Pedestrian entry — business hours, six days, with the gate absorbing it outside those hours.
- Reception — business hours, six days.
- Basement — day shift only, with the gate post covering entry at night when the basement is closed.
- Patrol — business hours plus a night round pattern.
- Supervision — one shift supervisor across the day shift.
Note what this plan does. It uses round-the-clock cover only where the risk is genuinely continuous, absorbs lower-volume periods into an existing post rather than creating a new one, and places supervision where decisions are made rather than spreading it thinly. A plan built by multiplying every position by three shifts would cost substantially more and secure the building no better.
Note also what it does not do. It does not merge the gate and the patrol, and it does not leave the basement unobserved while treating the building as covered.
Using the number
Once the posting plan exists, it does three things for the buyer.
It makes quotations comparable, because every agency is now pricing the same requirement rather than proposing its own. It makes under-delivery visible, because the duty chart states which post should be occupied at any hour and that can be checked. And it makes the cost explicable internally, because the number can be traced to a stated requirement rather than to a vendor’s recommendation.
For the cost side of the same calculation, our security cost calculator works from posts and shifts, and our guide to security guard costs in Maharashtra explains what the resulting figure is made of. When comparing the responses, how to choose a security agency sets out what to examine beyond the price.
Bryte produces a posting plan of this kind as part of a free site assessment, whether or not it leads to a contract, because a buyer who cannot state their requirement cannot evaluate anyone’s response to it. A written proposal follows within 48 hours.
Frequently asked questions
How many security guards do I need for my building?
It follows from the number of posts that must be occupied and the hours each must be covered, not from floor area or the number of units. List the positions that genuinely require someone present, decide the hours for each, convert those covered hours into people, then test the plan for places where it assumes one guard can be in two places at once.
How many guards does a 24-hour post require?
More than three. A post occupied round the clock needs 168 hours of cover every week, and one person provides a lawful duty pattern with a weekly day off, plus some absence. A quotation that staffs a 24-hour post with three people is either absorbing the shortfall or the post will be uncovered for part of the week.
Can one security guard handle both the gate and patrolling?
Not at the same time. A guard who leaves the gate to patrol has vacated the gate, and during that period the site’s primary control is unmanned. Where a site genuinely needs both functions simultaneously, that is two posts. Where it does not, the patrol can be scheduled for periods when gate activity is low, and that should be stated in the duty chart.
How do I compare two security quotations with different guard numbers?
Convert both to covered hours per post. Ask each agency to show how its headcount delivers the cover it claims, including the weekly off and absence. A lower headcount for identical cover is not efficiency; it is a difference in what is being promised. The duty chart, not the headcount, is the document to compare.
What is a duty chart and why does it matter?
A duty chart names each post, the hours it is occupied and the tasks performed at it, rather than listing people. It matters because it is the only document that lets a client check whether the site is actually covered at a given hour, and it converts a security contract from a headcount into a stated service.
Do I need fewer guards if I install CCTV?
Sometimes, but not in the way it is usually assumed. Cameras produce evidence after an event; guards intervene during one. Cameras can reduce the need for a fixed observation post, and they can extend the reach of a patrol. They do not replace a post whose purpose is to stop, question or refuse someone at the point of entry.