SOC Staffing Calculator
Size a SOC rota in FTE, including the 4.2–5 FTE per seat that genuine 24×7 coverage requires once shrinkage is funded.
Inputs
25 days leave, statutory holidays, sickness and training land at 18–25% in most countries.
A user-supplied assumption — salary, employer costs, tooling and training.
Total FTE Required
24.8FTE
FTE per Seat
5.25FTE
≈4.2 for 24×7 before shrinkage, ≈5.25 with 20% shrinkage.
Tier 1 FTE
15.8FTE
Tier 2 FTE
6.3FTE
Team Lead FTE
2.8FTE
Annual People Cost
$2,356,594
Rota Feasibility
Viable 24×7 rota — confirm the shift pattern is legal for rest periods
Step by step
Values used
Seats to staff concurrently = 3 seats; Coverage model = 24×7×365 — 168 h/week; Contracted hours per FTE per week = 40 hours/week; Shrinkage — leave, sickness, training, attrition = 20 %; Tier 2 analysts per tier 1 analyst = 0.4000 ratio; Analysts per team lead = 8 analysts; Fully loaded cost per FTE = 95,000 $/year
SOC Staffing
FTE per seat = coverage hours per week ÷ contracted hours per FTE ÷ (1 − shrinkage). Total FTE = seats × FTE per seat, plus tier 2 and leadership.
Leadership and cost
Team leads = (tier 1 + tier 2 FTE) ÷ span of control; annual cost = total FTE × fully loaded cost per FTE.
Total FTE Required
= 24.8 FTE
FTE per Seat
= 5.25 FTE
Tier 1 FTE
= 15.8 FTE
Tier 2 FTE
= 6.3 FTE
Team Lead FTE
= 2.8 FTE
Annual People Cost
= 2,356,594
How it works
168 ÷ 40 is 4.2, which is why a single 24×7 seat needs at least 4.2 FTE before anyone takes a day off. Dividing by (1 − shrinkage) funds leave, sickness and training, which pushes a realistic seat to about 5.25 FTE — the number most SOC business cases are missing. Under-funded rotas fail predictably: the fifth person is cut in budget review, then every holiday is covered by overtime until people leave, and the vacancy makes the coverage gap permanent.
Formulas
SOC Staffing
FTE per seat = coverage hours per week ÷ contracted hours per FTE ÷ (1 − shrinkage). Total FTE = seats × FTE per seat, plus tier 2 and leadership.
- 168
- Hours in a week — the true cost of 24×7
- contracted hours
- Hours per FTE per week, usually 37.5–40
- shrinkage
- Leave, sickness, training and attrition, typically 18–25%
Leadership and cost
Team leads = (tier 1 + tier 2 FTE) ÷ span of control; annual cost = total FTE × fully loaded cost per FTE.
- span of control
- Analysts one lead can realistically manage, 6–10
- fully loaded cost
- A user-supplied assumption
Frequently Asked Questions
How is SOC Staffing calculated?
FTE per seat = coverage hours per week ÷ contracted hours per FTE ÷ (1 − shrinkage). Total FTE = seats × FTE per seat, plus tier 2 and leadership. 168 ÷ 40 is 4.2, which is why a single 24×7 seat needs at least 4.2 FTE before anyone takes a day off. Dividing by (1 − shrinkage) funds leave, sickness and training, which pushes a realistic seat to about 5.25 FTE — the number most SOC business cases are missing.
Why does SOC Staffing matter?
Under-funded rotas fail predictably: the fifth person is cut in budget review, then every holiday is covered by overtime until people leave, and the vacancy makes the coverage gap permanent.
What values do I need to enter?
This calculator takes 7 inputs: Seats to staff concurrently, Coverage model, Contracted hours per FTE per week, Shrinkage — leave, sickness, training, attrition, Tier 2 analysts per tier 1 analyst, Analysts per team lead, Fully loaded cost per FTE. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
Why is 4.2 the magic number?
A week has 168 hours and a full-time analyst works about 40, so covering one chair around the clock takes 4.2 people even if nobody is ever ill or on leave. Any rota built on four is quietly relying on overtime.
Can a managed service replace the fifth FTE?
Often, yes — and that is usually the honest comparison. Outsourcing nights and weekends buys the expensive part of the coverage curve, but only works if the provider has authority to contain, not just to notify.