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VoIP Bandwidth Calculator

Calculate the on-the-wire bandwidth VoIP calls consume for a chosen codec, including RTP, UDP, IP and Ethernet overhead.

About VoIP Bandwidth Calculator

A G.711 call carries 64 kbps of audio but sends 50 packets a second, each wrapped in about 58 bytes of RTP, UDP, IP and Ethernet headers. That overhead adds roughly 23 kbps, so the real figure is closer to 87 kbps per call than the codec rate suggests. Provisioning trunks on the codec rate alone undersizes them by a third, and voice is the first traffic class users notice when a link saturates.

Formula

VoIP Bandwidth

Per-call kbps = codec payload + (header bytes × 8 × packets per second ÷ 1,000)

codec payload
Compressed voice rate before any headers
header overhead
RTP, UDP, IP and layer-2 bytes added to every packet

Worked example

With the default values below, VoIP Bandwidth Calculator returns Total Bandwidth Required of 348.80. Change any input above and every figure here is recalculated in your browser.

Inputs used

Concurrent callsminimum 0
4
Codec payload rateminimum 1 kbps
G.711 — 64 kbps
Packets per secondaccepts 10–100 pps
50 pps
Per-packet header overheadaccepts 20–120 bytes
58 bytes

Results

Total Bandwidth Required
348.80 kbps
Bandwidth per Call
87.20 kbps
Total Bandwidth Required
0.3488 Mbps
Overhead per Call
23.20 kbps
Monthly Data at 4 Hours a Day
18.84 GB

Step by step

  1. 1Values used
  2. 2VoIP Bandwidth
  3. 3Total Bandwidth Required= 348.80 kbps
  4. 4Bandwidth per Call= 87.20 kbps
  5. 5Total Bandwidth Required= 0.3488 Mbps
  6. 6Overhead per Call= 23.20 kbps
  7. 7Monthly Data at 4 Hours a Day= 18.84 GB

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is VoIP Bandwidth calculated?

Per-call kbps = codec payload + (header bytes × 8 × packets per second ÷ 1,000) A G.711 call carries 64 kbps of audio but sends 50 packets a second, each wrapped in about 58 bytes of RTP, UDP, IP and Ethernet headers. That overhead adds roughly 23 kbps, so the real figure is closer to 87 kbps per call than the codec rate suggests.

Why does VoIP Bandwidth matter?

Provisioning trunks on the codec rate alone undersizes them by a third, and voice is the first traffic class users notice when a link saturates.

What values do I need to enter?

This calculator takes 4 inputs: Concurrent calls, Codec payload rate, Packets per second, Per-packet header overhead. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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