VoIP codec reference
A codec turns voice into data for a call. Use this table to compare four common codecs, their estimated bandwidth, and where they are often used.
VoIP codec comparison
| Codec | Estimated bandwidth | Often used for |
|---|---|---|
| G.711 | 80–100 kbps | Business networks with reliable capacity |
| G.722 | 80–100 kbps | Wideband calls when every device supports it |
| Opus | ~40 kbps | WebRTC, mobile use, and changing network conditions |
| G.729 | ~32 kbps | Low-bandwidth links; support and licensing vary |
These estimates include common Ethernet, IPv4, UDP and RTP overhead at 20 ms packetisation. Real use can vary with packet size, IP version, security and tunnels. Last reviewed: . Technical references: RFC 3551 and RFC 7587.
How to choose
Start with a codec supported by the provider, phone system, and phones. Using the same codec from end to end usually avoids extra conversion.
For experienced users: transcoding can add delay, use processing capacity, and make faults harder to trace. Check the codec that was actually negotiated instead of assuming the first offered codec was used.
Related: voice codecs, codec comparison, and bandwidth calculator.