VoIP Bandwidth Calculator
Work out how much bandwidth your calls need, per call and in total, including RTP, UDP, IP and layer-2 overhead. Change any setting and the results update instantly.
All codecs with your settings
| Codec | ptime | Per call | Total |
|---|
How this calculator works
Each RTP packet carries payload = bitrate × ptime ÷ 8 bytes of audio, plus 12 bytes RTP, 8 bytes UDP and 20 bytes IPv4 (40 for IPv6), plus your link-layer overhead. Bandwidth is packet size × 8 × packets per second, where packets per second = 1000 ÷ ptime. The result is per direction: a call uses the same amount upstream and downstream.
Signalling (SIP) traffic is tiny by comparison and isn't included. Comfort noise and voice activity detection can lower real usage, but don't count on them for capacity planning.
Want the full explanation, with worked examples? Read How much bandwidth does VoIP need?
Frequently asked questions
How much bandwidth does one VoIP call use?
About 87 kbps per direction for G.711 over Ethernet at 20 ms, and about 31 kbps for G.729. Opus at 32 kbps uses about 55 kbps.
Should I size for upload or download?
Both. Voice is symmetric, so each call uses the same bandwidth in both directions. The upload side is usually the limit on asymmetric connections.
Does a VPN increase VoIP bandwidth?
Yes. Tunnel headers are added to every packet. WireGuard adds about 60 bytes per packet over IPv4, which can nearly double the bandwidth of a G.729 call.
What packet interval should I use?
20 ms is the standard and safest choice. 30 or 40 ms reduces overhead but adds delay and makes each lost packet more audible.