For the best call clarity, the minimum speed for VoIP phone calls is between 90 kbps (kilobits per second) to 156 kbps at the other end of the VoIP speed spectrum.
Generally speaking, the higher your upload speed (which is really what is meant by your Internet connection speed), the more reliably consistent the quality of your VoIP phone calls will be. Typically, only a broadband Internet connection can provide the minimum bandwidth for VoIP calls.
Each VoIP provider will have different recommendations regarding the minimum bandwidth for VoIP calls using their service. Some VoIP providers have a lower threshold for minimum speed — Vonage notes that it can support VoIP calls made at Internet connection speeds as low as 30 kbps, but recommends a minimum speed of 90 kbps for consistent quality. Popular residential VoIP provider magicJack requires a much higher VoIP speed of 128 kbps.
For more demanding VoIP call types, such as HD calls or video calls, the minimum speed is even higher. For instance, Skype recommends 1.2 mbps as the minimum bandwidth for VoIP HD video calls.
|Call Type||Recommended VoIP Speed||VoIP Provider|
|Low Quality Voice Call||30 kbps||Vonage|
|Best Quality Voice Call||30 kbps||Skype|
|Best Quality Voice Call||64 kbps||Vocalocity|
|Best Quality Voice Call||64 kbps||RingCentral|
|Best Quality Voice Call||90 kbps||Vonage|
|Best Quality Voice Call||128 kbps||magicJack|
|HD Video Call||1.2 mbps||Skype|