What Is Jitter? Causes and How to Fix It
Quick answer
Jitter is how much your ping changes from one moment to the next. Under 5 ms is very steady, 5–20 ms is usually fine, and above about 30 ms calls start to stutter and games rubber-band. It's mostly caused by Wi-Fi and by other traffic filling your router's queue.
Jitter in plain terms
Data travels across the internet in small packets. Ping is how long one packet takes to go to a server and back. If every trip took exactly 20 ms, your jitter would be zero. In real networks, trips vary — 18 ms, 25 ms, 19 ms, 60 ms — and jitter is the size of that variation.
Think of a bus that's meant to arrive every ten minutes. If it sometimes comes after two minutes and sometimes after twenty, the average might still be ten, but you can't plan around it. Jitter is the same problem for your data.
Why jitter matters
Video calls and games are real-time. If packets arrive unevenly — one after 10 ms, the next after 80 ms — the app has to wait or skip. You hear it as robotic or cutting-out voices and see it as frozen video or players jumping around.
Apps protect themselves with a "jitter buffer": they hold incoming audio or video for a short moment so late packets can catch up. A bigger buffer smooths things out but adds delay, which is why calls on an unstable connection often feel laggy as well as choppy. Streaming video uses a much bigger buffer, so it barely notices jitter at all.
How we measure it
We take the average difference between one ping and the next. For example, pings of 10, 12, 10 and 14 ms give jitter of (2 + 2 + 4) ÷ 3 ≈ 2.7 ms. Run the jitter test to see yours over 30 seconds; it also shows a live chart, so you can tell steady small wobbles from occasional big spikes.
| Jitter | What to expect |
|---|---|
| Under 5 ms | Smooth calls and gaming |
| 5–20 ms | Usually fine |
| 20–50 ms | Occasional stutter |
| Over 50 ms | Choppy calls, unstable games |
Different tools calculate jitter in slightly different ways, so compare results from the same test over time rather than across tools.
Common causes
- Wi-Fi. Radio is shared: your devices take turns, neighbours' networks compete for the same channels, and weak signal means retries. All of that shows up as uneven timing. It's the most common cause by far.
- Busy connection. When an upload or download fills the router's queue, packets wait different amounts of time depending on how full the queue is. This is the same effect as bufferbloat.
- Old router struggling with modern speeds and many devices.
- Mobile and satellite connections, where signal and network load change constantly.
- Congestion on your provider's network at peak times.
Find the cause in three tests
- Test on Wi-Fi where you normally sit, with nothing else running.
- Test with a cable next to the router. If jitter drops sharply, Wi-Fi is the cause.
- Run the bufferbloat test. If ping and jitter shoot up only while the test downloads or uploads, your router's queue is the cause.
If jitter is high even on a cable with nothing else running, and especially if it's worse in the evenings, the problem is likely on your provider's side.
How to reduce jitter
- Use a cable for calls and gaming. See Wi-Fi vs Ethernet.
- Move closer to the router, switch to 5 GHz or 6 GHz, or add a mesh point. See how to improve Wi-Fi speed.
- Pause backups and big downloads during calls.
- Turn on SQM or QoS in your router — see bufferbloat fixes.
- Restart and update your router, or replace it if it's very old.
- Talk to your provider if a wired, quiet connection still shows high jitter, with test results from different times.
Jitter is one of three numbers worth watching together with ping and bufferbloat. Gamers should also read how to reduce ping.
Jitter on mobile connections
4G and 5G connections often show more jitter than fixed broadband, because signal strength and the number of people using the mast change constantly. Testing near a window and at quieter times usually helps.