Ping, latency and jitter explained

Latency is how long data takes to make the round trip. Ping is the tool that measures it. Jitter is how much that time changes from one moment to the next.

Three words, one idea

• Latency is delay: the time for a small packet to go from your device to a server and for the answer to come back. It is measured in milliseconds (ms); 1,000 ms is one second.
• Ping is the name of the classic program that measures it, so people say "my ping is 40" to mean a latency of 40 ms.
• Jitter is unevenness: if one packet takes 30 ms and the next 90 ms, jitter is high even though the average looks fine.
• Packet loss is the fourth member of the family: packets that never arrive and must be sent again or done without.

Speed (Mbps) is how wide the pipe is. Latency is how long the pipe is. A wide pipe does not make it shorter.

What the numbers feel like

For jitter, lower is better: steady delay matters more to calls than low delay. When jitter is high, voices turn robotic and video freezes, because the app has to wait for late packets or drop them.

What causes delay

• Distance. Data cannot beat the speed of light in fibre. A server on another continent adds a delay that nothing at home can remove.
• The kind of connection. Fibre is quickest, then cable and good 4G or 5G. Satellites high above the equator add roughly half a second because of the distance; low-orbit satellite services are far quicker.
• Wi-Fi. A weak or crowded signal makes packets wait and repeat.
• A busy line. A large download or upload on one device makes everyone else's packets queue.
• The provider's network at busy hours.

How to measure it

Use our response time test for a quick figure from the browser. For the classic tool, open Command Prompt on Windows or Terminal on Mac and Linux and type:

ping 1.1.1.1

On Windows it sends four packets and stops. On Mac and Linux it keeps going until you press Ctrl and C. Read the time= value on each line and the summary at the end, which gives the minimum, average and maximum and any loss. To see whether the trouble is inside your home, ping your own router first (its address is the "gateway" in your network details): that should be a few milliseconds with no loss. If the router ping is poor, the problem is your Wi-Fi, not the internet.

How to improve it

1. Use a cable for the gaming console or work computer if you can. It removes Wi-Fi delay and jitter entirely.
2. Move closer to the router or use the 5 GHz band, which is less crowded than 2.4 GHz.
3. Pause big downloads, uploads and cloud backups during calls and games.
4. Choose the nearest server or region in the game's settings.
5. Restart the router if delay has crept up over days.
6. Some routers have a setting called QoS or SQM that keeps calls and games smooth when the line is busy.

See also our fuller list of fixes for slow Wi-Fi.