Jitter Test

Jitter is how much your ping changes from one moment to the next. A connection with 20 ms ping that stays at 20 ms feels smooth; one that jumps between 10 and 90 ms makes calls choppy and games stutter, even if the average looks fine. This test measures 30 seconds of pings and shows the jitter as the big number.

What causes jitter

Wi-Fi interference, a busy network, and queues in your router are the usual causes. On Wi-Fi, devices take turns to talk and neighbours' networks compete for the same channels, so timing becomes uneven. Jitter often rises when something else starts uploading or downloading, because packets wait in your router's queue for different lengths of time. Mobile connections show more jitter as signal strength and mast load change.

Why jitter matters for calls

Video and voice apps play audio in real time. When packets arrive unevenly, the app has to wait or skip, which you hear as robotic audio or see as frozen video. Apps use a small "jitter buffer" to smooth things out, but a bigger buffer adds delay — so a jittery connection makes calls both choppy and laggy. In games, jitter shows up as rubber-banding and players jumping around.

How we calculate it

The test sends four pings a second for 30 seconds and takes the average difference between each ping and the next. Pings of 10, 12, 10 and 14 ms, for example, give jitter of about 2.7 ms. The chart shows every ping, so you can tell steady small wobbles apart from occasional big spikes — the spikes usually matter more.

Find the cause

Run the test on Wi-Fi, then with a cable next to the router. If jitter drops sharply on the cable, Wi-Fi is the cause. If it's low on both while the line is quiet, but rises when someone downloads, your router's queue is the cause — the bufferbloat test confirms it. If it's high even on a quiet, wired connection, especially in the evenings, the problem is likely your provider's network.

How to reduce jitter

Switch to a cable, move closer to the router, or use the 5 GHz or 6 GHz band. Pause big downloads and backups during calls, and enable SQM or QoS on your router if available. Restart and update the router, and consider replacing it if it's several years old. More detail in what is jitter and how to improve Wi-Fi speed.

Jitter, ping and bufferbloat together

These three numbers describe how your connection behaves in real time. Ping is how long a round trip takes, jitter is how steady it is, and bufferbloat is how much it worsens under load. A connection can look fine on one and poor on another, so check all three — see what is ping and the ping test.