Erlang Calculator Call Center

Optimize call center staffing based on call volume, handling time, and service level targets

Advanced Erlang C Calculator

Advanced Erlang C Calculator

Optimize call center staffing based on call volume, handling time, and service level targets

📊 Input Parameters

Number of calls received during the selected interval
Time period for the call volume entered
Average duration of a call (talk time + after-call work)
Percentage of calls to be answered within target time
Maximum acceptable wait time for target service level
Maximum agent utilization percentage
Percentage of time agents are unavailable (breaks, training, etc.)

📈 Calculation Results

Traffic Intensity (Erlangs)
8.33
This represents the call load on your system. 1 Erlang = 1 continuous hour of call traffic.
Key Performance Metrics
Service Level
85.2%
Avg. Wait Time
8.7s
Prob. of Waiting
24.6%
Agent Occupancy
69.4%

📝 Staffing Summary

Based on your input of 200 calls per hour and average handling time of 300 seconds, the calculator recommends 12 agents to achieve your service level target of 80% of calls answered within 20 seconds. Accounting for 30% shrinkage, you’ll need to schedule 18 agents.
Your call center can expect to achieve an 85.2% service level with an average wait time of 8.7 seconds. Agents will be occupied 69.4% of the time, and about 24.6% of callers will experience some wait time.
Service Level Analysis
Agent Distribution
Performance Metrics

This Erlang C Calculator helps determine optimal staffing levels for call centers based on historical call patterns and service objectives.

Erlang Calculator for Call Centers: Optimize Staffing Like a Pro

Struggling with overstaffed/understaffed call centers? Our Erlang Calculator Call Center tool helps you:
✔ Predict agent requirements accurately
✔ Reduce operational costs by 15-30%
✔ Improve service levels (e.g., 80% calls answered in 20 sec)

How to Use the Erlang Calculator Call Center

  1. Input Key Metrics:
    • Calls per hour
    • Average handle time (AHT)
    • Target service level (e.g., 80/20 rule)
  2. Get Instant Results:
    • Agents required
    • Occupancy rates
    • Cost projections

Example:
For *100 calls/hour*, 5 min AHT, and 80% service level, you’d need 9 agents at 85% occupancy.

FAQs for Erlang Calculator Call Center

What’s the difference between Erlang B, C, and A?

Erlang B (blocked calls), C (queued calls), and A (traffic intensity). Our tool supports all three models.

Can I use this for blended call/chat centers?

Yes! Adjust AHT to include chat handling time.

How accurate is the Erlang formula?

90-95% accurate for homogeneous call volumes. For spikes, add a 10-15% buffer.

Is there a mobile app version?

Currently Web app.

How to calculate Erlang in Excel?

Follow these steps:
Calculate Traffic Intensity (A):
= (Total calls per hour × Average Handle Time in seconds) / 3600
Use Erlang Formulas:
Erlang B (Blocked calls):
= (A^N / FACT(N)) / SUMPRODUCT(A^ROW(INDIRECT("1:"&N)) / FACT(ROW(INDIRECT("1:"&N))))
Erlang C (Queued calls):
Use helper columns for complex sums [or Use our pre-built calculator].

How to calculate Erlang manually?

Basic manual method:
Compute Traffic Intensity (A) as above.
For Erlang B:
Calculate (A^N / N!) divided by Σ(A^k / k!) from k=0 to N.
For Erlang C:
Add a queuing probability factor: Pw = (A^N / (N! × (N/(N-A)))) / [ ... + Σ(A^k / k!)]

Which Erlang formula should I use for call centers?

Use Erlang C if calls queue (most modern call centers).
Use Erlang B if blocked calls are discarded (e.g., trunk lines).

Excel Shortcut Master – Boost your spreadsheet productivity with these essential Excel keyboard shortcuts

call center erlang calculator