The Erlang C probability that an arriving call must wait, for E erlangs on m agents, is (E^m/m!)(m/(m-E)) divided by [the sum of E^i/i! for i from 0 to m-1, plus (E^m/m!)(m/(m-E))].

field report · Checked 2026-09-25

Vendor
vendor-neutral
Product
not restricted
Subsystem
agent staffing
Deployment
any
Region
not restricted
Release range
revision current at 2026-09-25
Status
field report
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). Erlang B and Erlang C for voice and contact center sizing: source note erlang-traffic-engineering-erlang-c-formula. WarmTransfer. https://warmtransfer.net/knowledge/claims/erlang-traffic-engineering-erlang-c-formula

BibTeX

@misc{warmtransfer-claim-erlang-traffic-engineering-erlang-c-formula,
  title  = {Erlang B and Erlang C for voice and contact center sizing: source note erlang-traffic-engineering-erlang-c-formula},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/erlang-traffic-engineering-erlang-c-formula},
  note   = {Source note erlang-traffic-engineering-erlang-c-formula, checked 2026-09-25}
}

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