What Is Packet Loss? (And How to Test for It)

What Is Packet Loss? (And How to Test for It)

Blue strings of binary code running through the air to illustrate data packet transmission.

Packet loss is a connection issue where “packets” of data are lost before reaching their destination. Test for packet loss locally and over the internet with a simple command line tool to isolate the problem. Make changes to your network setup or contact your ISP to solve the issue.

Packet loss can play havoc with your network connection. Fortunately, testing for it is relatively straightforward on both a local connection and over the internet. Here’s what you need to know before you complain to your ISP.

What Is a Packet?

In networking terms, a packet is a small chunk of a larger message that has been divided up for efficient delivery. Packets are used because computer networks are “packet-switching” networks. This means that packets can travel and be processed independently of each other over the same connections in any order, before being reassembled once they reach their destination.

This is fundamental to the internet’s infrastructure, where a huge number of devices make up the larger network, all communicating and sending data at the same time. Without packets, data would be sent as one long stream, which becomes impractical once more than two devices are introduced.

Illustration of data packets routed throughout a computer network.
Anas Riad/Shutterstock.com

All data transferred over local and global computer networks is broken down into packets of around 1500 bytes. Internet protocol packets are made up of a header (which includes information like origin and destination IP addresses, packet types, and the packet number) and a payload (the data you’re transferring).

What Is Packet Loss?

Packet loss is what happens when one of these packets does not reach its destination. This results in incomplete data on the receiving end, requiring data to be sent again to successfully process the request.

Random packet loss can occur as part of “normal” network performance. It’s not desirable, and it can result in a slow network, interrupted streams, latency, and things not working as they are supposed to.

Packet loss is more evident in certain online activities, particularly gaming, streaming, and real-time voice and video communication. You may notice jerky motion in games, network timeouts, or random disconnection. Packet loss when streaming or voice and video calling can cause freeze frames, stuttering, robotic audio, or macroblocking (heavy pixelation caused by compression).

Though packet loss is bad, you don’t usually need to worry about it unless it’s a constant issue.

What Causes Packet Loss?

Much of the time, packet loss is caused by factors outside of your control. This could be due to problems with services you’re using, telecommunications infrastructure, or internet service provider outages. Packet loss can affect both local networks and the wider internet. If you’re experiencing problems on your local network, the issue is caused by a problem on your end.

This could be down to factors such as:

  • Problems with network hardware.
  • Interference on wireless or wired networks.
  • Software problems with computers and other devices.
  • High loads on network hardware (like routers, switches, or wireless repeaters).

How to Test for Packet Loss

You can test for packet loss over a local network or the internet. This can help you decide whether or not the problem is on your side or whether you need to get your ISP or telecommunications provider involved.

Test for Local Network Packet Loss

An easy way to test for packet loss is to use the ping console command. On Windows, you can do this by launching PowerShell (use the Search feature in the Start menu to find it).

Find Windows 11 using the search feature

First, figure out the address of your router by running the ipconfig /all command and looking for the IP address listed next to the “Default Gateway” entry. In most cases, this will be or

Now run ping <address> -t in PowerShell, where <address> is the IP address of your router. The ping command will run indefinitely, each time sending a single packet of data. Let it run for a bit, then hit Ctrl+C to cancel the command.

Run the "ping" command in PowerShell on Windows 11

Any packet loss experienced will be listed. Ideally, you want to see “0% loss” reported for this test. This means that the connection between your computer and your router isn’t dropping packets.

See whether your ping test encountered packet loss on Windows 11

To do this on a Mac or Linux computer, use the Terminal application. Run the netstat -nr|grep default command to see your router IP address listed at the top of the page. Now run ping <address> replacing <address> with the router IP address.

Run "ping" in Terminal for macOS

The command will run indefinitely, sending and receiving a single packet each time. Let it run then hit Control+C to cancel the command. You’ll see any packet loss listed. If you see “0% loss” then your local connection isn’t dropping packets.

Work out whether you're encountering packet loss with Terminal for macOS

Test for Internet Connection Packet Loss

You can use a similar method to test your internet connection for packet loss, except instead of your local router IP address you can use a website URL like howtogeek.com or google.com.

Internet speed test websites like speedtest.net or packetlosstest.com will also let you know about any dropped packets. You’re more likely to encounter packet loss over the internet since there can be many hops between your computer and a remote server which means more potential points of failure.

RELATED: How Do Internet Speed Tests Work? (and How Accurate Are They?)

How to Fix Packet Loss

If you suspect that the problem is on your side, eliminate as many causes as possible before changing too many variables. Restart your computer and apply any outstanding software updates. Do the same for network hardware, especially if it has been a long time since you’ve power cycled.

If your network equipment is under heavy load, test at a time when loads are lighter. Rather than doing this during the day when everyone is trying to use the internet, do it late at night when everything is off.

Fix Packet Loss on a Local Network

Wi-Fi is a common cause of lost packets on a local network. The obvious remedy is to use a wired network, even though that’s not always practical. At the very least you can test to see if the problem persists on a wired network to isolate Wi-Fi as the cause of your problems. Ideally, this would involve moving a laptop close to your router and connecting it up via Ethernet then running the above tests again.

If it turns out that Wi-Fi is to blame, you can take some steps to mitigate problems by removing sources of network interference and setting your channel accordingly. You may want to try switching between the 2.4Ghz and 5Ghz frequencies to see if that helps.

If you’re already using a wired connection, check and replace any cables that may be damaged. Powerline networks can be affected by interference too, resulting in packet loss. Try turning off large appliances and re-testing to isolate the source.

If your router is old and easily overloaded, replacing it with a modern mesh router system or high-performance Wi-Fi 6E router could be the answer.

Fix Packet Loss Over the Internet

Hardware can also be to blame for problems that go beyond your local network. Always restart your computer and your network hardware then test over a wired connection if you suspect this to be the case. If you have a separate modem (or a combined router-modem), consider that it too could be to blame. If you can test with other hardware, do so.

If you’re confident that the problem is your connection, it’s time to get on to your internet service provider or telecommunications company to remedy the problem. Tell them exactly what the problem is, what you’ve learned, and what sort of symptoms you’re having (like streaming problems, latency issues when playing games, slow web browsing, and so on).

Make a note of when you encounter these problems, whether it’s all the time, during heavy usage periods, or sporadically. Be aware that some service providers may bill you for a call-out if they find that there is nothing wrong with your connection. Borrowing a modem and router from a friend to rule out your own equipment could save you some money!

Check for Excessive Latency Too

Latency can be one of the biggest sources of connection strife, an issue that plagues even relatively “fast” connections like satellite internet. It’s one of the many reasons your internet connection can seem slow.

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