Blog
Articles, guides, and tips to help you get the most out of our calculators.
Erlang B vs Erlang C: Which Formula Do You Need?
Erlang B sizes trunk lines where blocked calls are lost. Erlang C staffs call centers where callers queue. Pick the wrong one and your capacity plan will be wrong.
Read moreHow to Calculate SIP Trunk Lines for Your Business
Size your SIP trunks correctly using Erlang B: find your busy-hour call volume, calculate traffic intensity, then apply the Erlang B formula for your blocking target.
Read moreCall Center Staffing: Erlang C Explained Simply
Erlang C calculates how many agents you need to answer a target percentage of calls within a set time. Here's exactly how the formula works and how to apply it.
Read moreTraffic Intensity: Erlangs, CCS, and Minutes Explained
Traffic intensity measures how much a telecom circuit is used. One Erlang = one circuit occupied for one hour. Here's what it means and how to calculate it.
Read moreGrade of Service: P.01, B.05 and What They Mean
Grade of Service sets how much call blocking you'll tolerate. P.02 is standard for business telephony, P.001 for emergency services. Here's what each level means.
Read moreHow to Plan for Peak Hour Traffic in Telecom Networks
Telecom networks are always sized for the busy hour, not daily averages. Here's how to find your peak traffic period, measure it accurately, and plan capacity for it.
Read moreVoIP Capacity Planning: SIP Trunks with Erlang Math
VoIP capacity planning combines Erlang B for SIP channel sizing with bandwidth math for codec selection. Get both right before you cut over from PRI to SIP.
Read moreThe 80/20 Service Level Rule: Staff Your Call Center Right
The 80/20 service level rule means 80% of calls answered within 20 seconds. Here's what it actually means, where it came from, and how to staff for it using Erlang C.
Read more7 Common Erlang Calculation Mistakes (and How to Fix Them)
Using average traffic instead of busy-hour, omitting wrap-up time, and picking the wrong formula are the three most costly Erlang mistakes. Here's all seven and how to fix them.
Read morePBX Trunk Sizing Guide: Traffic Analysis to Provisioning
A complete walkthrough of PBX trunk sizing: collecting traffic data, calculating Erlangs, running Erlang B, selecting your GoS target, and provisioning the right number of lines.
Read moreAgent Occupancy: What It Is and Why 85% Is the Limit
Agent occupancy measures how much time agents spend on calls. Above 85–90%, Erlang C queues become unstable. Here's what occupancy means and how to optimize it.
Read more