Support Staffing Calculator
How many agents do you need to hit your FRT SLA? Enter your conversation volume, average handle time, and target service level — Erlang C does the rest.
Agents needed
6
to answer 80% of conversations within 5 min
Traffic intensity (Erlang A)
4.00
30 conv/hr × 8 min AHT ÷ 60
Achieved SL (6 agents)
91.8%
SL with 5 agents
70.3%
About this calculation
Uses the Erlang C queuing model — the industry standard for call center and support staffing. Assumes a steady-state queue with no abandonment. Real-world results vary with conversation clustering and handling time variance.
Monitor your real team metrics in SupportmanTraffic intensity (A): Volume per hour × AHT in hours. If you get 30 conversations/hour and each takes 8 minutes, A = 30 × (8/60) = 4.0 Erlangs. You need at least 5 agents just for the system to be stable.
Why you need more than A agents: With exactly A agents the queue grows without bound. In practice you need A + buffer agents to hit any meaningful service level target.
Limitations: Erlang C assumes Poisson arrivals (random) and exponential handling times. Real support conversations cluster (Monday mornings, after releases) and have high AHT variance. Treat this as a baseline — add 10–20% for real-world conditions.