Skip to main content

Documentation Index

Fetch the complete documentation index at: https://docs.vobiz.ai/llms.txt

Use this file to discover all available pages before exploring further.

Estimate Calls Per Second (CPS) and simultaneous concurrency for your voice campaigns. Adjust the inputs below - results recalculate live.

​
How the math works

The calculator uses two formulas:
  • CPS = Total daily volume ÷ (Calling hours × 3600)
  • Concurrency = [(Connected calls × Avg duration) + (Unanswered calls × Avg ring time)] ÷ (Calling hours × 3600)
Concurrency accounts for the “hold time” of both connected and unanswered calls - a busy ringing line still occupies a channel.

​
Understanding the metrics

  • Calls Per Second (CPS) - The rate at which your system initiates new calls. If CPS exceeds your account limit, calls get throttled. See CPS.
  • Concurrency - Number of calls active at the same instant (ringing + connected). This is your channel requirement. See Concurrency.
  • Pickup rate - % of dialled numbers that connect to a person. India outbound dialers typically see 15–30%; a verified opt-in list can hit 40–60%.
  • Avg ring time if unanswered - How long a call rings before timing out. Default 14s. Lower values free channels faster on busy campaigns.

​
Best practices

  • Monitor peak-hour traffic - typically 1.5× daily average.
  • Use shorter ring times (10–12s) on outbound dialers to recycle channels faster.
  • Match your SIP trunk’s concurrent_calls_limit to the calculator’s concurrency value plus 20% overhead.
  • Predictive dialers should target CPS slightly below their licensed rate to leave headroom for retries.

Concurrency

How concurrent calls are counted and rate-limited.

CPS

What CPS is and why it matters at scale.

Purchase capacity

How to upgrade your concurrency / CPS limits.

Number utilization

Get the most out of your DID inventory.