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Contact Center Concurrent User Capacity Estimator

The Contact Center Concurrent User Capacity Estimator estimates how many simultaneous agent or voice sessions a connection can support after reserving headroom for other traffic. It is useful for contact center planners comparing a WAN circuit, SD-WAN path, or internet connection with the per-session bandwidth used by voice and desktop applications.

The result separates raw bandwidth capacity from a safer planning capacity. By entering available bandwidth, estimated bandwidth per active session, and a utilization target, you can see both the theoretical session limit and the practical limit after headroom. This is a planning estimate rather than a guarantee because codecs, encryption, retransmissions, screen sharing, CRM traffic, and traffic bursts can all change real usage.

Capacity inputs

Mbps
Kbps
%
%
Result
—
simultaneous sessions
Raw capacity—
Usable bandwidth—
Reserved headroom—

1. Enter link capacity

Enter the bandwidth available to the contact center on the path you want to evaluate.

2. Set per-session demand

Enter the estimated bandwidth consumed by one simultaneous active session, including voice and any traffic you intentionally want to bundle into the estimate.

3. Choose utilization

Set the maximum percentage of the remaining link you want active sessions to consume. A value below 100% preserves operating headroom.

4. Reserve other traffic

Enter the percentage of total bandwidth expected to be used by non-session traffic such as signaling, CRM activity, monitoring, or other applications.

5. Review capacity

Use the main result as the planning limit and compare it with the raw capacity shown in the breakdown.

Usable Mbps = Available Mbps × (1 − Reserve% / 100) Planning Kbps = Usable Mbps × 1,000 × (Utilization% / 100) Concurrent sessions = floor(Planning Kbps / Kbps per session)

Available Mbps — Total link bandwidth in megabits per second.

Reserve% — Share of the total link held for other traffic.

Utilization% — Maximum share of usable bandwidth assigned to simultaneous sessions.

Kbps per session — Estimated bandwidth for one active session.

Assumptions: The model treats each active session as having the same average bandwidth demand and does not model burstiness, packet loss, codec changes, or application-specific QoS.

What the result means

Use the main result as a planning estimate under the assumptions and inputs shown above.

For production decisions, compare the estimate with measurements and system-specific limits.

Given

  • Available bandwidth: 200 Mbps
  • Per-session demand: 180 Kbps
  • Target utilization: 75%
  • Other traffic reserve: 20%

Calculation
Usable bandwidth = 200 × (1 − 0.20) = 160 Mbps
Planning bandwidth = 160 × 1,000 × 0.75 = 120,000 Kbps
Concurrent sessions = floor(120,000 / 180) = 666

Result
666 simultaneous sessions

Under these assumptions, planning for about 666 active sessions keeps the modeled session load within the selected utilization target.

Why is the planning capacity lower than raw capacity?

The planning result first removes the bandwidth reserved for other traffic and then applies the utilization target. Raw capacity assumes the entire remaining bandwidth could be devoted to sessions.

What should I include in bandwidth per session?

Include the average network demand you want attributed to one active user or call. If voice and desktop traffic share the same path, you can combine them when you have a reasonable per-session estimate.

Can I enter 100% utilization?

Yes, but it leaves no modeled headroom for bursts, retransmissions, or measurement error. For operational planning, many teams intentionally choose a lower target based on their own service objectives.

Does this estimate call-center staffing needs?

No. It estimates network session capacity, not staffing, occupancy, shrinkage, or queue performance. Workforce calculations need separate arrival-rate and handling-time inputs.

Why can real capacity differ from this result?

Actual traffic varies with codecs, packet overhead, encryption, screen sharing, CRM usage, retransmissions, and network quality. Validate the estimate with measured peak traffic before using it as a deployment limit.