How Much Bandwidth Do I Require For VoIP? - XINIX

How Much Bandwidth Do I Require For VoIP

As home users and businesses stop using traditional analog telephone services, to adopt VoIP (Voice Over Internet Protocol), one of the main challenges becomes the allocation of the adequate amount if bandwidth to your Internet telephone service.

What amount of your current bandwidth is required for high-quality voice calls? This is among the most frequently asked questions by our customers. To get the right answer, begin by asking yourself the following key questions:

  • What is the actual download and upload speed of data that your ISP (Internet Service Provider) delivers?
  • What other applications and services on your network consume a percentage of the available bandwidth?
  • Are there any QoS (Quality of Service Settings) that you can adjust to optimize your current network for VoIP?

Minimum and Recommended Bandwidth for VoIP Services

Generally, the bandwidth that is required by your VoIP phone service is dependent upon the number of simultaneous calls that you wish to make. The table that is shown below indicates the least amount of bandwidth that is needed for making calls from a account, as well as the speeds that are recommended for optimal performance:


Number of Simultaneous Calls Least Amount Of Bandwidth Required Recommended Speed
1 100Kbps Up and Down 3MBps Up and Down
3 300Kbps Up and Down 3MBps Up and Down
5 500Kbps Up and Down 5MBps Up and Down
10 1MBps Up and Down 5-10MBps Up and Down


How Does VoIP Utilize My Bandwidth?

The response to this query is both easy and difficult. Voice Over Internet Protocol services utilize a range of codecs to compress and decompress voice data, letting it travel through the internet with optimal efficiency. utilizes codecs that need roughly 100Kbps traveling up from your telephone line and down to your telephone line per second for every call. Therefore, if you have 3 individuals all on calls at the exact moment, the minimal requirement is 300Kbps up and 300Kbps down.

Apart from that, since the Internet ‘pipe’ into your place of residence or business is being utilized for other functions as well; web surfing, receiving and sending email, file and data transfers, point-of-sale systems, web-based office services and so on, there are still lots of candidates that are contending for the same bandwidth.

How To Determine Your Functional Bandwidth

Knowing the amount of bandwidth that you have really helps. But then, your ISP (Internet Service Provider) will perhaps only confirm the amount you signed up for, this is also referred to as the advertised ‘up to’ value, as in ‘up to 30Mbps’ or ‘up to 100Mbps’.

The best way you can determine the strength of your bandwidth is by running a throughput test via sites like This is going to provide to with a clear picture of your real-time bandwidth. However, it is crucial to note that this metric may vary with respect to the amount of bandwidth that all the other variety of applications you are using need at any specific point in time. The results of this test also vary depending on the location you are at when you carry out the testing.

Remember that your speed of upload is often slower that your speed of download, therefore, you have to make sure that the lower number of your speed of upload matches your requirements. Since the majority of providers don’t guarantee constant bandwidth in addition to the up-to value, we recommend that you add a 5x to a 10x safety margin when you estimate the bandwidth.

Calculating The Bandwidth That You Require

If you know that your ISP is capable of sustaining a specific speed, just multiply the amount of the expected simultaneous phone calls by 100Kbps. If you are dealing with an ‘up to’ ISP, then it would be a great solution to add the safety margin that is mentioned above in order for you to maintain the needed bandwidth even upon when your internet service weakens.

For instance, 10 simultaneous users would need 1MBps (10 x 100Kbps x the safety margin), meaning that it would be a smart move for you to allow for 5 – 10Mbps both up and down. Depending on the rest of the applications and service that are utilizing your internet connection, 3 – 5Mbps may be enough, or you may have to increase your bandwidth. This has to be assessed on a basis of case-by-case as every organization varies.

Optimizing Your QoS (Quality of Service)

Currently, high-quality voice calls are the norm, however, you have to put in some effort to maintain the quality. One excellent way of evaluating the capacity of your VoIP is through the VoIP test at (it works best with Firefox and Safari). This tool allows you to evaluate the performance of your network by simulating one, three, five or even ten simultaneous calls from your office to the systems of

In addition, some, but not all routers are able to prioritize voice services so that the effect of using other service and applications does not reduce the voice quality. To avoid audio issues that arise as a result of data and voice competing for the same bandwidth, ensure that the QoS settings if your network router are as indicated below, so that they give priority to the broadcast of voice packets to your WAN connection.

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

Lastly, if your router has an ALG (Application Layer Getaway) functionality, that needs to be disabled. Apart from that, we recommend that you disable the SPI (Stateful Packet Inspection) function; sometimes, the router isn’t able to handle the high rate of incoming voice packets when the SPI feature has been enabled. But then in all cases, consult with your security expert before you change the configuration settings.

We hope that these guidelines will enable you to establish the amount of bandwidth that you require for supporting high-quality VoIP phone service. If you have any other specific questions, please leave them below in the comments section or let us know by contacting us directly.

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