This is a VoIP bandwidth calculator. Select your Layer 2 header (Ethernet or MP), your Layer 3 and above header and the voice payload, and it should calculate the required bandwidth.
and then to calculate the bandwidth, we need the packets per second (PPS):
Note 1: For IP we get 20 bytes, UDP 8 bytes, RTP 12 bytes. When it is compressed with cRTP we compress this to 2 to 4 bytes.