What is packet loss, and how do you fix it?

Everything you send over the internet is cut into packets, typically up to 1,500 bytes each, which travel independently and are reassembled at the far end. When a router's queue is full, a Wi-Fi frame is corrupted by interference, or a cable flips a bit, the packet is discarded. The receiver never sees it.

What happens next depends on the application. Web pages, downloads and streaming use TCP, which notices the gap and resends, so loss shows up only as slower throughput. Games, voice and video chat use UDP and cannot afford to wait: a lost packet is a position update or a slice of audio that is simply gone. That is why 2% loss barely dents a speed test but makes a shooter unplayable.

Rough thresholds for real-time use:

The ping test sends a stream of probes from your browser to our server and reports how many came back, alongside latency and jitter. Run it for at least a minute: loss is often bursty, and a ten-second sample can miss it entirely. The connection quality test repeats the measurement while loading the connection, which exposes the loss that only appears when someone in the house is downloading.

From a terminal you can test against any address, which is what makes it possible to narrow down where the loss happens:

Windows 11

ping -n 100 192.168.1.1
ping -n 100 1.1.1.1

The summary line reads Packets: Sent = 100, Received = 98, Lost = 2 (2% loss). The first command tests only the link to your router (use its real address; the router IP guide shows how to find it). The second tests the whole path to a public resolver.

macOS and Linux

ping -c 100 192.168.1.1
ping -c 100 1.1.1.1

The summary reads 100 packets transmitted, 98 packets received, 2.0% packet loss.

Xbox

Press the Xbox button, then open Profile & system > Settings > General > Network settings > Test network speed & statistics. The result screen lists packet loss as a percentage alongside latency and speeds.

PlayStation 5

Settings > Network > Connection Status > Test Internet Connection reports speed and NAT type but does not show a packet loss figure. Test from a PC or laptop plugged into the same cable or Wi-Fi network instead; the result applies to the console too.

Loss has a location. Testing in stages isolates it in a few minutes:

1. Ping your router. Any loss here is inside your home: Wi-Fi, a cable, a switch or the router itself. Over Ethernet, loss to the router should be exactly zero.
2. Ping a nearby public address such as 1.1.1.1. Loss that appears here but not to the router is on your ISP's side: the line to the house, the local node or the provider's network.
3. Run a per-hop test. On Windows, pathping 1.1.1.1 discovers the route and then sends 100 probes to every hop, printing the loss at each one; it takes a couple of minutes. On macOS and Linux the equivalent is mtr, installed through Homebrew or your package manager. Read the results carefully: a router that rate-limits replies to its own address shows loss on its line while forwarding perfectly, so trust only loss that persists on every hop after it.

The traceroute tool on this site shows the path from our server toward a host, with latency per hop, which is useful for checking whether a bad hop sits inside your ISP or further out on the internet.

• Wi-Fi. The most common cause by far. Interference from neighbors' networks, microwaves and cordless phones, distance, walls and too many devices on one channel all corrupt frames. Wi-Fi retransmits lost frames, which converts some loss into jitter, but under heavy interference packets are dropped outright.
• A damaged or substandard Ethernet cable. A kinked cable, a crushed one under a chair, a loose connector or an old Cat 5 run can produce errors that force the link to drop packets or renegotiate to a lower speed. Yes, a bad cable causes packet loss, and it is the first thing to swap because it is the cheapest.
• An overloaded router. When uploads saturate the line, the router's buffers fill and it drops whatever arrives next; cheap or old routers also drop packets when their CPU is maxed out by many connections.
• Network adapter and driver problems. Outdated drivers, power-saving modes on Wi-Fi adapters and faulty USB adapters all cause intermittent loss on one device only.
• ISP line faults. Noise on a DSL line, a weak cable signal, water in a street cabinet, or congestion at the local node in the evening produce loss that every device in the house sees, usually with a time-of-day pattern.
• Overheating hardware. Modems and routers in cupboards or behind TVs throttle and drop packets when hot.
• Software on the device. Aggressive firewalls, VPN clients and "network optimizer" utilities occasionally discard packets or fragment them badly.

On a PC

1. Switch from Wi-Fi to Ethernet, even temporarily, and re-test. If the loss disappears, the problem is Wi-Fi and the fix is a cable, a 5 GHz or 6 GHz band, a better router position or a mesh node near the PC.
2. Replace the Ethernet cable with a known-good Cat 5e or better, and try a different port on the router.
3. Update the network adapter driver from the PC or motherboard maker's site, and in the adapter's power settings turn off Allow the computer to turn off this device to save power.
4. Pause cloud backups, torrents and game updates, then re-test. If loss vanishes when the upload stops, enable QoS or SQM on the router so the queue cannot overflow.
5. Temporarily disable VPN software and third-party firewalls to rule them out.

On Xbox and PlayStation

1. Use a wired connection. Consoles tucked into a media unit get poor Wi-Fi.
2. Power-cycle the modem, router and console, and leave the router off for a full minute.
3. Run the console's network test again at a quiet time of day and compare with the result during peak hours; a difference points at congestion rather than your equipment.
4. Keep NAT open or moderate so you are not forced through relay servers that add their own loss; our port forwarding guide explains how.

When it is the ISP

If loss shows up to every public address, from every device, over Ethernet, and persists after a router restart, it is on the provider's side. Record a few ping -n 100 or pathping results at different times of day and send them with your support request; a line fault is far more likely to be fixed when you can show 4% loss at the first hop beyond your router than when you report "lag". Ask them to check line errors and signal levels on your connection.