What Is VoIP Latency?

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Voice over Internet Protocol (VoIP) phone systems work by transferring data packets of audio between your phone and a recipient’s phone. Normally, these data packets travel so fast between VoIP phones that there are no noticeable gaps in your conversation. However, in some circumstances, VoIP calls can experience latency issues, or in other words, delays in data transfer.

In this guide, we’ll explain everything you need to know about VoIP latency, including how to solve common latency issues with your VoIP calls.

How Is VoIP Latency Measured?

You can measure your VoIP phone system’s latency for free using online latency checkers from Fusion Connect, RingCentral, and other VoIP service providers. These tests report your system’s latency in milliseconds (ms). Note that some tools may use the term ‘ping’ instead of latency—these two terms are often used interchangeably.

Latency in the range of 20-150 ms is considered good. Delays this short are essentially undetectable by ear and you’re unlikely to notice any problems with your call quality.

If you experience latency greater than 150 ms, the delay can become noticeable. Your call recipient could hear echoes of your voice or you could end up talking over each other. If you’re on a video call and using a VoIP phone for audio, your audio and video transmissions could get out of sync.

If latency exceeds 300 ms, it can be difficult to carry on a conversation. There may be long pauses and it may be hard to avoid talking over one another.

One-way vs. Two-way Latency

Latency is typically measured as the time it takes for data packets to travel one way from your phone to your recipient’s phone. However, you may occasionally see measurements of two-way latency.

Two-way latency is the time it takes for data to travel from your phone to a call recipient’s phone and back. While data packets don’t actually make a roundtrip during VoIP calls, an acknowledgement that each data packet was delivered to your recipient is sent back to your phone.

In most cases, two-way latency is roughly double the one-way latency time. So, a good two-way latency for VoIP calling is less than 300 ms.

Signs and Symptoms of VoIP Latency Issues

High latency in your VoIP calls can make it difficult to have a smooth conversation. Some of the common problems caused by VoIP latency issues include:

  • Echoing
  • Overlapping audio
  • Audio and video falling out of sync

These issues can lead to delayed responses, slowing down your conversation and making it harder to understand a speaker’s tone. Latency issues can also result in you and your call recipient repeatedly talking over each other.

How To Improve VoIP Latency

VoIP latency issues can be caused by a variety of problems with your phone system. We’ll explain the most common problems and how to fix them.

Not Enough Bandwidth

Not having enough bandwidth for your internet connection is one of the most common causes of high VoIP latency.

Insufficient bandwidth is like having a pipe that’s too narrow to carry all of the data you want to transmit. As a result, data packets—including VoIP data packets—will get congested and travel more slowly.

A good way to diagnose this problem is to disconnect some devices to reduce your bandwidth use, then make a VoIP call. If disconnecting devices eliminates latency issues, then you likely need more bandwidth.

There are two main ways to get more bandwidth. The first is to upgrade your business’s internet plan. Internet service providers typically offer multiple plan tiers with varying amounts of bandwidth.

The second is to upgrade your router. Older routers have limited bandwidth compared to newer models. So an old router could prevent you from using all of the bandwidth available through your internet service plan.

Firewall Software

Firewall software checks every data packet that travels between the internet and your devices for malware. This process is good for VoIP security, but it can also increase latency if your firewall settings are too strict.

You can fix this problem by choosing less stringent settings for your firewall. You can also whitelist your VoIP software so that VoIP data packets are allowed to pass through without malware scans.

Incorrect Codecs

A codec is the software that converts your voice into digital data packets. There are many different types of codecs, some of which take longer to encode voice and decode data packets.

You can change the codec your VoIP system uses in your VoIP software’s settings. The G.722 codec is best in most cases, but you may find that the G.711 codec works better for your VoIP system.

Outdated VoIP Hardware

Old VoIP hardware could also be the cause of high latency. Old hardware doesn’t always work well with new software, which can result in delayed audio transmission. You can test whether your hardware is the culprit by making a call with a newer device, like a smartphone with a VoIP app.


VoIP latency is a measure of how long it takes for audio data packets to travel from your phone to a recipient’s phone. If your VoIP phone system has latency longer than 150 ms, it could cause problems with your calls such as echoing or overlapping audio.

To fix latency issues, check your internet connectivity and bandwidth, firewall software, codecs, and VoIP hardware. If you’re still having problems, many of the top business VoIP providers offer personalised help to ensure you get the best possible call quality from your phone system.


What is a good VoIP latency?
Latency of 150 milliseconds or less is considered good for VoIP calling. With latency longer than 150 milliseconds, you may experience echoing or delayed audio on your calls.
How do I fix VoIP latency issues?
VoIP latency issues often result from problems with your internet connection. Check to make sure that you have a strong internet connection with enough bandwidth to support all of your devices. If you have an older router, that could be limiting the bandwidth of your WiFi network.
Why is my phone echoing?
Echoing audio in a VoIP phone call can be due to high latency. You may be able to reduce your phone system’s latency and eliminate echoing by upgrading your router or improving your internet connection. You may also need to disable your firewall or modify its settings.
Written by:
Eamonn is an experienced B2B writer and content manager, having managed and grown several B2B business blogs in the fitness and hospitality space.