When using a VoIP phone service, the quality of your calls and how many lines you can support will largely depend on the bandwidth of your internet connection — the faster the better. For example, the average internet connection in the US has a 10 Mbps upload speed, which can support 22 VoIP phone lines comfortably.
How Many Phones Can My Internet Connection (Mbps) Support?
The faster your internet connection, the more VoIP phone lines it can support. For example, a 500 Kbps upload speed will support a maximum of five lines whereas a 10 Mbps upload speed will support a maximum of 100.
The results of your speed test will give you two numbers: your download speed and your upload speed. Because you’re limited by the lower of the two numbers (which is almost always your upload speed), we’ll refer to that as your bandwidth.
Now, find the closest match to your bandwidth in the chart below:
|Bandwidth (Upload Speed)|
VoIP Mbps Speed Test: How To Do The Math
You can also do some simple math to calculate exactly how many VoIP lines your internet connection can support:
- Multiply your upload speed by 1000. This converts the units from Mbps to Kbps, so if your speed is already expressed in Kbps then skip this step.
- Divide your result from step 1 by 445. This will tell you the recommended number of phone lines your connection can support.
- Divide your result from step 1 by 100. This is how many phone lines you can support in a perfect world where your internet connection was stable and consistent and no bandwidth was being used for other activities, like browsing or downloading.
For example, here are the results of my own speed test:
So using my upload speed of 11 Mbps, the recommended number of VoIP phone lines that my internet connection can support is 24 and the maximum is 110.
Maximum vs. Recommended Number of Lines: What’s the Difference?
The number of VoIP lines you can support doesn’t only depend on your internet speed. It also depends on how much of your bandwidth is available for VoIP use versus other uses like internet browsing, email, online software, web-based POS systems, etc.
Our recommended number of lines takes into account these other browsing activities, as well as expected fluctuations in your internet speed throughout the day. Cable internet speeds tend to fluctuate, whereas newer fiber connections are more stable. You can learn more about different connection types in our guide How to Set Up Internet for Your Business.
What Do The VoIP Mbps Speed Test Numbers Mean?
- Upload Speed – Your connection’s upload speed, measured in megabits per second (Mbps), is typically lower than your download speed because this reflects the actual bandwidth available to your computer.
- Download Speed – The maximum amount of data your connection can receive, measured in megabits per second (Mbps). In the rare case where this number is lower than your upload speed, then this is your actual bandwidth.
- Ping – The amount of time it takes for your computer to communicate with a server. On a VoIP phone call, this constitutes the latency (or delay) between you and the person you’re speaking with. Small delays aren’t noticeable, and a ping speed below 100ms is generally acceptable.
What is Bandwidth?
Bandwidth is maximum rate at which your network can transfer data. And because VoIP technology transmits your voice as data, it’s one of the key factors in determining how many concurrent phone calls your internet connection can handle.
Bandwidth is measured by your download and upload speed – that is, the rate that information travels to and from your computer. Whichever of the two numbers is lower is your bandwidth.
Because most users download much more than they upload, most internet service providers (ISPs) design their networks to allow for faster downloads than uploads. This is why your upload speed is most likely lower than your download speed.
Each VoIP phone call typically requires 100 Kpbs up and down – or 1/10th a Mpbs. So if your upload speed is 10 Mpbs, then your network can theoretically manage up to 100 VoIP phone calls at once. The actual number, however, is closer to 10 or 20 calls because of other bandwidth usage.
Bandwidth Limitations for VoIP
|Bandwidth (Upload Speed)|
There are two main reasons why you need to give some leeway when measuring bandwidth:
Internet speeds fluctuate throughout the day. When there are more users in your local area using the internet, speeds can vary up to 21 percent, according to one study of broadband internet connections.
Another factor is web browsing. If you’re using the same internet connection to check email, stream videos, or run web applications, then your VoIP lines will have to compete for bandwidth. Heavy internet activity (such as the concurrent use of email, YouTube, and Spotify) takes about 1 Mbps download per user. Fortunately, they don’t require nearly as much upload bandwidth, which is typically the more important factor for VoIP phone calls. The exception, of course, is if you do a lot of upload-intensive work such as sharing videos/graphics or collaborating on files. If so, then this number could be a lot higher for you.
The other number you’ll see on the speed test is ping time. This measures the latency (or delay) between your computer and the network you’re connecting to, so it roughly translates to the delay you’ll hear when speaking on the phone. Anything below 100ms is a safe number. Here’s why:
Delays aren’t usually noticeable on the phone unless they’re over 250ms, so if your ping time is below 100ms and the person you’re speaking with has a ping time below 100ms your ears shouldn’t perceive any delay. The reason we leave an extra 50ms for leeway is because of the delay the VoIP system takes to encode and decode the voice to and from data.
Improve a Bad Connection by Allocating More Bandwidth
If you have a small business, most broadband connections will give you more than enough bandwidth for VoIP calls. With an average upload speed of over 6 Mbps in the US, a typical connection can manage 12 or more lines without much challenge.
On the other hand, if you need more than 12 lines and/or if your connection speed is significantly lower, then your VoIP call quality may suffer. Fortunately, there’s still an easy hack that can improve your call quality — even with low bandwidth:
Bandwidth allocation is when you specify which internet activities get priority on your network. In other words, you can allocate a certain percentage of your bandwidth to your VoIP service. Then when your network gets strained, it will prioritize your VoIP traffic by slowing other activities (like internet browsing, download/uploading files) before it slows your calls.
To set up bandwidth allocation, you need to adjust the Quality of Service (QoS) settings on your router. You can usually do this online by going to the website of your router provider (i.e. Netgear, Linksys, D-Link, Cisco, etc.) and logging into your control panel, or search for “[Your Router] bandwidth allocation” on Google.
Does My Choice of VoIP Provider Affect Call Quality?
Yes. VoIP providers differ in how they handle your calls, such as how they encode your signal from voice to data. One of the biggest factors that can affect your call quality, however, is how many data centers they operate. Smaller companies who just have one data center, for example, may be prone to more issues when their network is strained. By contrast, larger companies can offer more reliable service by spreading their service out across locations.
We recommend Nextiva as the best VoIP phone service provider for small businesses because it delivers the right balance between its standard features, customer support, and price. In fact, we use Nextiva in our own office. You can read our VoIP phone service buyer’s guide here.
The Bottom Line
Most broadband connections are well over the requirements to support 1-10 concurrent VoIP phone calls. With a high-speed business connection, that number can be much higher.
Remember, though, that VoIP calls have to compete with other traffic-intensive internet activities on your network, so if your business performs regular resource-heavy tasks like collaborating on graphics or uploading a lot of files, you’ll have to factor that into your VoIP capabilities.