What is the Erlang C formula and how does it work?

Erlang C is a mathematical formula that calculates the probability of a caller having to wait in a queue, given the number of agents, call volume, and average handle time. It models the random arrival pattern of calls using Poisson distribution, making it far more accurate than simple division-based staffing estimates. The formula was developed by Danish mathematician A.K. Erlang and is the global standard for call center workforce planning.

What is the difference between Erlang B and Erlang C?

Erlang B calculates the probability of a call being blocked (receiving a busy signal) in a system with no queue — if all agents are busy, the call is lost. Erlang C, on the other hand, assumes calls will wait in a queue if no agent is immediately available. For most modern call centers with hold queues, Erlang C is the correct formula to use.

What is a good service level target for a call center?

The industry standard is 80/20 — meaning 80% of calls answered within 20 seconds. However, optimal targets vary by industry. Premium support lines may target 90/10, while cost-sensitive operations might accept 70/30. The right target balances customer experience against staffing costs.

What is shrinkage in call center staffing?

Shrinkage is the percentage of time agents are unavailable to handle calls despite being on shift. It includes breaks, lunch, training, meetings, coaching sessions, system downtime, sick leave, and other off-phone activities. Typical shrinkage ranges from 25% to 35%. Accounting for shrinkage is critical — without it, you'll be significantly understaffed.

How do I calculate my Average Handle Time (AHT)?

AHT = Average Talk Time + Average Hold Time + Average After-Call Work (ACW) time. Talk time is the actual conversation duration. Hold time is when the caller is on hold. ACW (or wrap-up time) includes note-taking, CRM updates, and any post-call tasks. Most ACD (Automatic Call Distribution) systems track these components automatically.

What is agent occupancy and what's the ideal rate?

Occupancy is the percentage of time agents spend handling calls versus waiting for calls. An occupancy rate of 80-85% is generally considered ideal. Below 70% suggests overstaffing. Above 90% leads to agent burnout, increased attrition, and degraded service quality as agents have no recovery time between calls.

Is the Erlang C formula accurate?

Erlang C is highly accurate for inbound call center planning and is the industry standard used worldwide. However, it has limitations: it assumes infinite queue capacity (no callers hang up), it doesn't account for call abandonment, and it assumes a steady-state system. For most practical purposes, these limitations are minor, and Erlang C provides excellent staffing estimates.

How often should I recalculate staffing levels?

Recalculate whenever your call patterns change significantly. Most centers review staffing quarterly and adjust for seasonal patterns. You should also recalculate when AHT changes (due to new products, policy changes, or training), when call volume trends shift, or when you change your service level targets.

What is traffic intensity in Erlangs?

Traffic intensity measures the total call workload on your system, expressed in Erlangs. It's calculated as (calls per hour × average handle time in seconds) / 3600. One Erlang represents one agent fully occupied for one hour. You always need more agents than Erlangs — for example, 10 Erlangs of traffic might require 14-15 agents to maintain an 80/20 service level.

Can I use this calculator for chat and email staffing?

Erlang C was designed for single-channel voice calls where agents handle one interaction at a time. For chat (where agents handle multiple simultaneous conversations) or email (which isn't real-time), you'll need modified approaches. However, if your chat agents handle one chat at a time, Erlang C can provide a reasonable estimate.

How many agents does an insurance call center need?

It depends on your call volume, product lines, and time of year. An insurance contact center handling 150 calls per hour with 6-minute AHT at 80/20 service level needs approximately 30-32 raw agents, or 43-46 after 30% shrinkage. During open enrollment, these numbers can increase by 50% or more.

What is a typical AHT for insurance calls?

The median AHT for insurance call centers is around 6 minutes (360 seconds). Claims intake calls average 8-10 minutes. Policy change requests take 4-6 minutes. Simple billing inquiries may be 2-3 minutes. Open enrollment calls for health insurance average 10-15 minutes due to plan comparison complexity.

How do I staff for open enrollment?

Start planning 10-12 weeks before open enrollment begins. Hire and train temporary staff specifically for enrollment inquiries. Consider extending operating hours. Many carriers add AI chat or IVR self-service options to handle routine enrollment questions. Use the peak season toggle above to model the staffing impact.

How should I plan for catastrophe event call surges?

Develop a CAT (catastrophe) staffing plan that identifies: overflow agent pools (cross-trained staff from other departments), partner outsourcing firms on standby, extended hours protocols, and priority routing for affected policyholders. Volume can spike 3-5x overnight — you can't hire your way out of it; you need pre-planned overflow capacity.

What shrinkage rate should insurance call centers expect?

Insurance call centers typically see 27-33% shrinkage. The higher end accounts for mandatory continuing education requirements, compliance training, and licensing maintenance. Multi-state operations often have additional training requirements for state-specific regulations.

Should claims and policy service be in separate queues?

Generally yes. Claims calls (especially FNOL) are emotionally charged, longer, and require specialized skills. Blending claims and routine policy service in one queue makes accurate Erlang C modeling difficult because the AHT variance is too high. Model them as separate workloads for more accurate staffing.

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Insurance Call Center Staffing Calculator

Erlang C calculator with insurance industry benchmarks. Plan staffing for claims processing, policy service, and open enrollment peaks.

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Seasonal Planning:

Standard call volume — no seasonal adjustment applied

Call Center Parameters

Calls Per Hour150

Total incoming calls per hour across all lines

Average Handle Time (AHT)6m

Includes talk time + after-call work

Target Service Level80%

% of calls answered within target time. Industry standard: 80%

Target Answer Time20s

Maximum wait time in seconds. Standard: 20s

ShrinkageShrinkage accounts for breaks, training, meetings, sick time, and other non-productive time that reduces agent availability.30%

Typical range: 25-35%

Cost Per Agent Per Hour (optional)

Fully loaded cost for monthly cost estimate

Agents Needed

19 raw + 9 for shrinkage

Service Level

80.44%

Avg Speed of Answer

22s

Occupancy

78.95%

Probability of Wait

24.42%

Immediate Answer

75.58%

Traffic Intensity

15 Erlangs

Estimated Staffing Cost

Per Hour

$672

Per Month (160 hrs)

$107,520

Insurance Benchmarks

AHT Range

4m – 9m

Median: 6m

Service Level Standard

80/20

Occupancy Target

78-85%

Acceptable Abandonment

< 3%

Typical Shrinkage

27-33%

Source: LOMA Insurance Contact Center Benchmarks, 2025

Call Center Staffing for Insurance

Insurance call centers are among the most complex contact center operations. Agents handle policy servicing, claims intake, coverage questions, billing disputes, and regulatory disclosures — each requiring deep product knowledge and compliance awareness. Average handle times in insurance consistently exceed general contact center benchmarks because of the documentation and verification requirements inherent in every interaction.

Open enrollment periods create the most predictable staffing challenge. For health insurance carriers, Q4 call volumes can spike 50% or more as consumers compare plans and complete enrollment. P&C insurers face unpredictable surges following catastrophic events — a major hurricane or wildfire can multiply call volume 3-5x overnight, requiring robust contingency staffing plans.

Regulatory compliance adds another dimension. Agents must consistently disclose policy terms, confirm understanding, and follow state-specific scripts for certain transactions. This drives longer calls and necessitates regular compliance training, which increases shrinkage. The cost of a compliance failure — regulatory fines, E&O exposure, policyholder lawsuits — far exceeds the cost of adequate staffing.

Key Challenges

•Open enrollment spikes of 50%+ require seasonal hiring plans
•Catastrophe events create unpredictable 3-5x volume surges
•Complex regulatory and compliance disclosure requirements per state
•Multi-line product knowledge (auto, home, life, health) across agents
•High documentation requirements extend AHT beyond typical centers

Common Call Types

Claims filing and status inquiriesPolicy changes and endorsementsCoverage questions and comparisonsBilling and payment inquiriesOpen enrollment and new policy applicationsRenewal processingComplaint handling and escalations

Staffing Tips

1Model open enrollment separately — it's a fundamentally different workload requiring dedicated staffing plans
2Build a catastrophe response staffing plan with pre-identified overflow resources and cross-trained agents
3Separate first-notice-of-loss (FNOL) claims intake from ongoing claims inquiries — FNOL calls are longer and more emotional
4Track compliance adherence per agent; one missed disclosure can result in regulatory action
5Consider dedicated queues for complex products (life, commercial) vs. simpler lines (auto, renter's)

Compliance Note

State insurance department regulations require specific disclosures during policy transactions. PCI-DSS compliance for payment processing. Call recordings often required for regulatory audits. E&O (Errors and Omissions) exposure makes accurate call handling critical.

FAQ

Insurance Staffing FAQ

Compliance starts with every call.

Call Optix monitors 100% of insurance calls for disclosure compliance, claims handling quality, and customer sentiment. Automatically flag missing disclosures and identify training opportunities before they become regulatory issues.

You've planned your staffing. Now ensure every agent on every call meets your compliance standards.

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