VoIP bandwidth calculator
Work out how much upload and download your simultaneous calls need for each codec, and whether your internet plan has comfortable headroom.
How this is calculated
Each call sends one audio packet every packet interval in each direction. Each packet carries the compressed audio plus 40 bytes of IP, UDP and RTP headers and 18 bytes of Ethernet framing. A VPN adds roughly another 50–60 bytes per packet. At a 20 ms interval that's 50 packets a second, so G.711 works out to about 87 kbps each way.
Voice is light, but it needs to arrive on time. The calculator flags a plan as comfortable when voice uses less than about a third of the upload, leaving room for everything else. Whatever the numbers say, enable QoS on your router so voice goes first when the link is busy. See our call quality guide.
NBN upload speeds shown are typical maximums for each tier. Real speeds vary by provider, technology and time of day, so run a speed test and use the custom option for an accurate answer.