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How Do I Test My Internet Speed for VoIP?

by Kevin Bartley

How do you test your Internet speed for VoIP? Use a VoIP network test - a free diagnostic that checks your Internet for a variety of VoIP markers.

A key factor of VoIP call quality is your Internet speed. Low speeds can degrade calls, causing breaks, delays, and dropped connections. A simple VoIP quality test can assess your office Internet speed, along with your general preparedness for VoIP.

What is a VoIP test?

All information on the Internet is passed from one endpoint to another via data packets. As an Internet-based technology, VoIP is no different. Calls are sent to and from callers via data packets that travel across the web. If some of these packets are "dropped" in transit, the lost packets affect the quality of the call. Dropped packets can lead to missing audio, grainy voice quality, or the outright termination of a conversation.

A VoIP test essentially assesses the way your Internet connection handles data packets. More specifically, most VoIP tests will measure the jitter, latency, and upload/download bandwidth of your Internet connection. All of these components affect the way your Internet connection handles data packets. In turn, they determine the quality of your VoIP calls.

Here are some of the terms you'll encounter in your VoIP test results.


Jitter causes poor audio quality in a call, usually in the form of choppy sound. Jitter is the variation in packet transit delays, measured in milliseconds. The lower your jitter is, the better.


Latency causes a delay in sound transmission. Latency, measured in milliseconds, establishes the time it takes for sound to travel between two callers. In a more technical sense, latency measures how long it takes for a data packet to travel between two endpoints. Again, the lower the latency, the better.


Upload/Download speed (bandwidth) is the maximum throughput of your Internet network. Bandwidth greatly affects all the components of your VoIP call. The measurement is calculated in bits per second. In this case, the higher your bandwidth, the better.

What do I need to run a VoIP test?

There are many free VoIP tests available on the web that run in your browser window. Some of these tests require Flash or Java to run. Make sure you have the latest browser version you can run a test without any problems.

You don't need a VoIP phone to test your preparedness for VoIP. You can test your network from any laptop or desktop computer connected to your Internet connection. You're simply testing the way packets behave on your network.

For better results, run the VoIP test when your office is the busiest, during peak Internet hours. This will give you a more accurate assessment of how much bandwidth you actually have to spare for VoIP. If your VoIP connection is not prepared for peak usage, expect call degradation at the busiest times.

As an example, if you have an office Internet connection of 20 Mbps, but 10 Mbps is being used for file downloads, videos, and other Internet data, then the actual bandwidth available for VoIP is closer to 10 Mbps. That's why you should test when everyone is in your office, using your resources.

Understanding your VoIP test results

A VoIP test should only take a few seconds to run. The test will monitor your Internet speed and present the findings in terms of jitter, latency, and bandwidth. These measurements will give a good indication if your Internet speed is ready for VoIP.

OnSIP Internet speed test

We recommend less than 10 milliseconds for jitter, less than 150 milliseconds for latency, and 100 kbps of both upload and download bandwidth for each employee in your office.

To assess whether you have enough bandwidth for the office, you need to know how many employees are using the Internet and for what purposes. The average VoIP call uses about 100 kbps of bandwidth for both upload and download throughputs.

For example, the bandwidth needs of a dental supply store with 10 employees, only one of whom is on the phone at a time, differs from that of a software call center in which all 10 employees are on the phone all day long.

If you're unsure of your call volume, a good rule of thumb is to estimate that 1/10 of your organization will be on the the phone at any given time.

Here are some handy conversions:

  • 1 VoIP call = 100 kbps
  • 1 VoIP call = .1 Mbps
  • 100 kpbs = .1 Mbps

What if my network is not ready for VoIP?

First, don't worry. It's possible to see bad results for any number of reasons. But none of those reasons should stop you from getting business VoIP. With a few minor tweaks or phone calls, you can fix your Internet speed. Poor VoIP test results are usually caused by either your ISP or your router.

Internet Service Provider (ISP)

Plug a computer directly into your modem with an Ethernet cable, and repeat the VoIP test on that computer. If your speeds are still low, you can rule out the router as the problem. You're most likely dealing with an ISP-level issue.

Some ISPs manipulate VoIP traffic in specific ways that may affect the outcome of your test results. Try to find some support articles on this topic for your provider. Look up topics such as bandwidth throttling, traffic prioritization, and service-wide disruptions that may be affecting your test results.

If these don't help, it's time to call your ISP's support line. Before you speak to a customer service representative, make sure that you've looked at the Service Level Agreement (SLA) for your ISP. This is the fine print you agreed to when you signed up for your ISP's service. The SLA will designate, in writing, the upload/download throughput you're entitled to as a customer.

If the the upload/download speeds you're getting are less than the numbers in the SLA, take a screenshot of your VoIP test results. Tell the support staff you have proof your speeds are not meeting the SLA. They will likely give you some suggestions for how to fix the problem. If you still can't get the speeds you want, ask them to lift your bandwidth cap to the appropriate levels.

On the other hand, if you are getting the speeds you agreed to in the SLA, and you're missing the marks in the VoIP test, it might be time to consider lifting the bandwidth cap on your Internet service. Ask your ISP what options and pricing there are for lifting the bandwidth cap to meet your VoIP needs.


Try the test we discussed above: plug your computer directly into the router with an Ethernet cord, and run the VoIP test again. If you can pass the VoIP test with this configuration, it probably means that there's something wrong with your router.

Some routers come equipped with Application Level Gateways (ALGs) that automatically deter or block VoIP traffic. Consult your router's user manual, and disable any ALGs that might block VoIP packets. These technologies include SIP ALGs, SIP Stateful Packet Inspection (SPI), and SIP Transformations. To learn more about how to do this, you can read about our NAT and firewall traversal recommendations here.

As far as VoIP prioritization goes, enabling certain features on your router such as Quality of Service, VLANs, dual-band shaping, and MU-MIMO can create ideal traffic flows for VoIP. We recently wrote a blog on the top business VoIP routers and the best features for running business VoIP. If you're router is simply not primed for VoIP, there are many affordable alternatives on the market today. Even tri-band 802.11ac routers have entered the reasonable price range for small businesses.

The Key to Call Quality Is Internet Speed

Call quality issues with VoIP generally come down to the Internet speed, including markers such as jitter, latency, and bandwidth. A VoIP test allows you to see where you stand in terms of your own Internet connection.

Most business-grade Internet services are capable of managing VoIP calls. Ultimately, your VoIP preparedness boils down to the innate capabilities of your Internet service, the hardware involved (such as routers), and the number of active Internet users in your office. The VoIP test is simply a way to gauge how these three factors interact.

Even if your office Internet isn't ready for VoIP, there's nothing stopping you from upgrading or troubleshooting your Internet connection. With business VoIP, technical shortcomings on your end don't require in-person services from the phone company. You can order more bandwidth, or fix a few settings, or switch to a DIY phone system and get it up and running in less than an hour.

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