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How Much Bandwidth is Needed for VoIP?

Businesses who use VoIP, or are looking to switch to VoIP, often wonder how much bandwidth is needed to support their VoIP phone system. VoIP phone systems depend on your Internet network to route calls. So there are things you need to know about setting up your Internet network to ensure you have the best call quality possible. The first step is understanding how VoIP uses bandwidth to function, and how much bandwidth you will need for your system.

How does VoIP use bandwidth?

To summarize, VoIP uses your Internet network’s bandwidth to operate. Bandwidth determines how quickly you can send data via the Internet during a given period of time.

This is where VoIP comes in. VoIP systems transform audio (voice) data into codecs by compressing and decompressing it. Then, it sends those codecs across the Internet to reach the other phone line. In order to do this, it needs a minimum amount of bandwidth from your network. To do it quickly and efficiently, it often needs more bandwidth than the minimum required.

How much bandwidth do I need for VoIP?

The amount of bandwidth needed for VoIP depends on how many phone lines you have running at once. For instance, if you are a small company with only 5 users who only sometimes use your phone lines, your bandwidth needs will be much different than a medium company with 20 users all using their phone lines regularly.

Take a look at these bandwidth requirements and recommendations:

Number of Concurrent CallsMinimum Bandwidth RequiredIdeal Bandwidth
1100 Kbps3 Mbps
3300 Kbps3 Mbps
5500 Kbps5 Mbps
101 Mbps5-10 Mbps
151.5 Mbps10+ Mbps
202 Mbps10+ Mbps

As you can see, most phone lines require 100 kilobits per second (Kbps) to support an audio phone call. That means if 3 employees are using their phone lines at the same time, your network will require 300 Kbps to support all 3 calls. To calculate the minimum bandwidth you need, use this simple formula:

It’s also important to keep in mind that these numbers are minimum requirements to support phone calls. It does not mean those calls will be of the highest possible quality. If you are using a unified communication system, the amount of bandwidth needed for VoIP will be more than the minimum listed here. To get the best voice quality results and best VoIP experience overall, we recommend choosing the “ideal” bandwidth listed above.

How to Figure out your Bandwidth

Figuring out exactly how much bandwidth your network allows is the first step to optimizing your VoIP system. Your bandwidth depends on a few things:

  • Router or modem
  • Installed web browsers
  • Internet settings and configurations
  • Internet Service Provider (ISP)

The type of service your ISP provides you with is the number one factor in determining bandwidth capabilities. The best way to determine your bandwidth is to simply call your provider and ask about your bandwidth. They will likely tell you that your bandwidth supports “up to” a certain amount, such as “up to 50 Mbps” or “up to 150 Mbps.”

You can also test your bandwidth or “Internet speed” by doing a simple test using online resources such as This will tell you your upload and download speeds, as well as your functional bandwidth.

Keep in mind that bandwidth usage and Internet speed also depend on how many devices are also using the Internet at the same time. In other words, if you have many devices connected to the Internet at once, your bandwidth will be more used up and each device may run slower.

How to Troubleshoot VoIP Bandwidth Issues

Are you experiencing VoIP lagging (aka voice latency), which is causing you to question your bandwidth? There are several things you can do. 

1. Look into latency

Keep in mind that while some voice latency is normal for VoIP systems, too much will cause issues for your business communications. The “acceptable” or normal amount of latency for VoIP systems is between 150-300 milliseconds. Any more than this window is considered “too much.” Learn more about VoIP latency and how to troubleshoot it.

2. Adjust QoS Settings

UDP/5060 – Priority: High
UDP/6060 – Priority: High
UDP/16384 to 32768 – Priority: High

Internet-based devices have built-in Quality of Service (QoS) settings via their routers. This allows you to “prioritize” bandwidth for some devices over others, depending on what you use on a regular basis. If you are using your phone system regularly, you want to adjust these settings to give sufficient bandwidth to VoIP. We recommend adjusting QoS settings to the following to best support VoIP:

3. Determine your type of codecs

As we mentioned, VoIP compresses and decompresses data using tools called codecs. There are a few different types of codecs, and each requires different amounts of bandwidth to operate. It’s possible your VoIP provider uses codecs that require a high amount of bandwidth. You can always talk to your provider about what types of codecs they use. If this type is not optimal for your business or takes up too much bandwidth, you can consider switching to a different provider.

4. Upgrade your bandwidth

Although it will cost a bit more, the single best way to get the bandwidth needed for VoIP is to invest in more bandwidth. You should consider this a worthwhile investment, since your Internet helps your business operate on a day-to-day basis. Upgrading your bandwidth will improve your communications across the board, making all your Internet-based devices run quicker and more smoothly.

To find out more about VoIP phone systems, take a look at the top benefits of VoIP for business and our VoIP vs. landline guide. To learn more about VoIP’s cost benefits, take a look at our cost guide.

If you’re ready to get started comparing VoIP options, 360Connect can help! Our free service helps you find the most cost-efficient VoIP suppliers. They can help you figure out how much bandwidth you need to set up your VoIP system, as well as any other questions you may have. Visit us here to get started!

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