Do I Have Enough Bandwidth For VoIP?

VoIP Bandwidth. Innocenti / Cultura / Getty

Question: Do I Have Enough Bandwidth For VoIP?

One of the main factors that grant PSTN a small advantage over VoIP is voice quality, and one of the main factors that affect voice quality in VoIP is bandwidth. For a brief glimpse on bandwidth and types of connection, read this article. Over here, we try to figure out, for any particular case, whether the bandwidth available is the bandwidth required.


This question is quite important in order to get good quality calling, but also important for those using mobile data plans. They will want to know how much of their data VoIP calls are taking. 

Normally, 90 kbps is sufficient for good quality VoIP (provided, of course, that other factors are favorable too). But this can be rare commodity in areas where bandwidth is still very expensive, or in corporate contexts where limited bandwidth has to be shared among many users.

In case you are a residential user, try to avoid dial-up 56 kbps connections for VoIP. Although it will work, it will very likely give you a very bad VoIP experience. The best bet is a DSL connection. As it goes beyond 90 kbps, you are good. For companies that have to share bandwidth and have to configure their VoIP hardware accordingly, administrators have to be realistic and lower or raise their quality settings according to the real bandwidth available per user.

Typical values are 90, 60 and 30 kbps, each resulting in a different voice quality. Which to choose will depend solely on the bandwidth/quality trade-off the company wants to make.

What makes the bandwidth settings adjustable are the codecs, which are algorithms (program segments) that are present in VoIP equipment for compressing voice data.

The VoIP codecs that offer better quality require more bandwidth. For instance, G.711, one of the best-quality codecs around, requires 87.2 kbps, while iLBC requires only 27.7; G.726-32 requires 55.2 kbps.

In order to know how much bandwidth you actually have and how suitable it is for your VoIP needs, you can use the many online speed tests available for free. There are tools that are more precise and accurate, for more technical results. An example is this VoIP bandwidth calculator.

It is important to underline that the amount of bandwidth required and amount of data transferred during calls depends on the app or service used, which in turns depends on technical factors like the codecs used. For instance, Skype consumes a lot of data as it offers high definition voice and video. WhatsApp takes much less, but still too much compared to lightweight apps such as Line. At times, for smoother communication, people choose to eliminate video for better voice quality, due to limitations in bandwidth.