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Calculate the minimum number of agents needed to meet your service level target.
Last verified: March 2026
The Erlang C formula calculates contact centre agent requirements based on call volume, average handle time, and service level targets. Enter your parameters below to determine the minimum staffing needed. The calculator also returns occupancy rate — the key indicator of agent sustainability. Optimal occupancy is 78–84%; above 85% triggers burnout risk.
WITH STANDARD SHRINKAGE (35%)
Required Headcount
13 FTE
8 agents ÷ 0.65 shrinkage factorService Level Target80.0% — Below Target
CriticalBelow TargetTargetOptimal
Agent Occupancy63.0% — Light
LightOptimalWarningCritical
Industry Context
Industry SL Target80/20 Rule
Optimal Occupancy78-84%
Answer Time Target20s
Drives Agent CountAHT
Key:63% occupancy suggests overstaffing. Check your shrinkage percentage — if it's below 28%, you may be underestimating unavailable time. Also verify AHT includes after-call work. Try the Shrinkage Calculator to validate your assumptions.
Note: Erlang C assumes random call arrivals and no abandonment. For high-abandon queues or complex multi-skill environments, consider simulation-based staffing. Always validate shrinkage assumptions with the Shrinkage Calculator.
Occupancy Benchmarks
Below 70%
OverstaffedHigh idle time. Review shrinkage assumptions or reduce scheduled FTE.70–77%
LightAcceptable for complex queues or agent experience priority.78–84%
OptimalSweet spot. Sustainable productivity with adequate recovery time.85–89%
WarningBurnout risk. Quality degradation likely within 60-90 days.90%+
CriticalUnsustainable. Expect attrition spike and AHT inflation.
Frequently Asked Questions
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Source: Erlang C queuing model · WorkforceAnalyst.com · 2026