The reliability and number of lines you can support for your voice-over-internet protocol (VoIP) will almost entirely depend on the bandwidth of your internet connection. Use our free VoIP speed test to measure your bandwidth, and read on to learn more about how bandwidth affects your setup and what you should do if you get a poor test result.
How Many Phones Can My Internet Connection Support?
As a general rule, the fastest internet connection can support the most phone lines. For example, a 500 Kbps upload speed will usually support a maximum of five lines. On the other hand, a 10 Mbps speed can typically support as many as 100 lines. Your speed test results will tell you how fast your connection is, and therefore, how many lines it can support. Check out our guide to business phone systems for more detailed information.
The results of your speed test will give you two particularly important numbers: your download speed and your upload speed. Your phone system’s capability will be limited by the lower of the two numbers, which is almost always going to be the upload speed. This will be your bandwidth. Find the closest match to your bandwidth in the chart below:
Number of Lines Based on Your Bandwidth
|Bandwidth (Upload Speed)|
Maximum vs Recommended Number of Lines: Knowing the Difference
Your speed isn’t the only factor in deciding the number of lines you can support. It also depends a great deal on how much of your bandwidth is available for phone calls versus other uses like web browsing, video streaming, and all of the activity on your connected devices.
The maximum number of lines field works under the assumption that all of your network bandwidth is being used for calls, while the recommended field takes into account all of the other network activity that is likely to be going on in your office.
When selecting an internet service provider (ISP), you may be limited to what’s available in your local area. If not, do research on what ISPs offer the fastest packages. For more information, check out our guide on how to set up the internet for your office.
How to Do a Manual VoIP Speed Test
While our VoIP test is accurate, some readers might need to do a manual calculation of how many lines they can support. This is simple:
- Multiply your upload speed by 1,000: You need this to convert from Mbps to Kbps. If your speed results are already expressed in Kbps, you can skip this.
- Divide your result from step 1 by 445: This will tell you the recommended total number of lines your connection can support.
- Divide your result from step 1 by 100: This is how many lines your system can support if you use your network for absolutely nothing else other than VoIP calls.
For example, here are the results of my own speed test. In order to better simulate a busy office network, I left several connected devices running, such as multiple smartphones, game consoles, and tablets:
In these conditions, my results show an upload speed of 11 Mbps. As such, the recommended number of VoIP phone lines that my internet connection can support is 24 and the maximum is 110.
What the VoIP Speed Test Numbers Mean
In order to fully understand bandwidth test results, let’s take a look at what the VoIP speed test numbers mean. We’ll also define some common terminology that comes up when measuring a network so that you can better interpret your results.
This is how fast your network is able to upload information, such as files and more, to the internet. This is the most accurate reflection of your network’s actual bandwidth.
This number reflects the maximum amount of data your network can receive per second. If this is somehow lower than your upload speed, this is the number that most accurately reflects your available bandwidth.
Ping is the measure of the amount of time it takes for your machine to communicate with a server. On a VoIP call, this has a direct correlation with any delays you might hear during calls. Small delays aren’t noticeable; a ping speed below 100 ms is fine in the majority of cases.
Jitter refers to how accurately packets of data travel across your connection and arrive in the correct order. If your jitter is higher than 30 ms, you will likely experience bad call quality in your VoIP service.
VoIP Bandwidth Requirements
Bandwidth is one of the key factors in determining how many concurrent calls your network can handle. It is measured by your download and upload speed. As mentioned above, the lower of the two numbers is, the more accurate representation of your bandwidth.
As a general rule, VoIP calls usually require 100 Kbps, or 1/10 of an Mbps. Therefore, if your upload speed is 10 Mbps, your network should be able to manage up to 100 VoIP calls at once. However, the fact that there is likely other network activity going on means this number is usually closer to 10 or 20 calls.
Bandwidth Limitations for VoIP
|Bandwidth (Upload Speed)|
There are two important things to note when measuring bandwidth. First, internet speeds fluctuate during the day depending on how many people in your area use the internet. In fact, speeds can vary up to 21% within the time frame of one average workday.
Another factor is web browsing. When you and your staff are checking email, streaming video, and hopping on Zoom calls, your VoIP lines will be competing for bandwidth. Fortunately, these don’t require much upload bandwidth, so a strong connection should be able to handle phone calls and all of your other web activity simultaneously.
What to Do If You Get a Poor Bandwidth Test Result
Most business internet packages will give you enough bandwidth for VoIP calls. Even a typical home connection can manage 12 or more lines without much challenge. However, if you need more than 12 lines and you have a slow connection, your VoIP call quality will likely suffer.
If you have a poor test result, there are a number of things you can do. First, disconnect all unnecessary devices from your network. For example, you can tell staff to take their personal smartphones off of Wi-Fi, or disconnect machines that are not currently in use.
You can also reach out to your ISP about upgrading your internet package. Most mainstream providers in the United States offer all different kinds of packages to meet different needs. While this will result in your organization spending more money, it is also a virtual investment in making sure that you are getting the most out of your business VoIP service.
What to Do If You Continue to Experience Poor Call Quality
If you have found that your current ISP service gives you the speed you need, but your call quality is poor, then you should consider switching providers for your business phone service, as some providers are better suited for heavy call traffic or multiple extensions and users than others. Luckily, there are a number of VoIP business phone services to choose from, and it is fairly easy to switch providers while keeping the same number.
We suggest looking at RingCentral. The voice-over-internet-protocol (VoIP) platform offers support for multiple lines and also comes with advanced features like video conferencing and the ability to connect call data to your favorite customer relationship management (CRM) solutions. They even offer a 15-day free trial so that you can try it out for yourself.
As an effort to assist during the difficult COVID-19 times, RingCentral is now free for K-12 educators, health care providers, and nonprofits.
Useful VoIP Resources
Check out the following articles for more detailed information on VoIP systems:
- VoIP vs Landline: What’s the Best Small Business Phone System: We broke down the key differences between landline and internet-based VoIP systems.
- Things to Consider When Setting Up VoIP Phone Service: Everything you need to consider before adopting your own business VoIP service.
- Small Business VoIP Service: Who Is the Best: Check out our comparison of the best VoIP systems on the market today.
- VoIP Service User Reviews: Hear what our readers think of today’s leading VoIP systems.
For more guidance on setting up a VoIP system, consider downloading our How to Set up Your Business Phone System e-book, which can help you step through the process.
Most standard broadband connections should be able to support one to 10 VoIP calls at once. With a premium connection, that number could be even higher. Knowing the strength of your network is a valuable thing when considering a VoIP system, which is why it is important to check your speed before you make the switch from a landline network and before changing providers.
If your bandwidth can support VoIP service, we recommend RingCentral to anyone looking for a powerful business phone system. The service offers features like unlimited calling, toll-free numbers, and video chat for as low as $19.99 per month, making it a great option for businesses with growing teams. Click here to start your 15-day free trial.