What is jitter, and why it makes you lose fights
UPDATED
Jitter is how much your ping jumps around. Why 40ms with no jitter beats 25ms with spikes, what counts as good, and how to fix it.
Ping tells you how long a packet takes to reach the server and come back. Jitter tells you how much that time changes from one packet to the next. A connection with a steady 40ms ping feels better than one that jumps between 15ms and 70ms, even though the second one has a lower average.
Why jitter feels worse than high ping
Games are built to handle latency. Lag compensation, client-side prediction and interpolation all assume your delay is roughly constant. When it suddenly changes, the game's predictions are wrong: enemies teleport, your shots register late, and you get killed behind cover. That is the “rubber-banding” feeling.
How jitter is measured
The usual definition (and the one Rekt-al Net uses) is the average difference between consecutive pings. If your pings are 20, 22, 21 and 40ms, the differences are 2, 1 and 19ms, so the jitter is 22 / 3 = 7.3ms. One spike is enough to push it up, which is exactly the point.
What counts as good jitter?
| Jitter | What it feels like |
|---|---|
| under 5ms | Perfect. You will not notice it. |
| 5 to 15ms | Fine for almost every game. |
| 15 to 30ms | Noticeable in shooters. Peeks and trades feel inconsistent. |
| over 30ms | Rubber-banding. You have a real excuse. |
The usual causes
- Wi-Fi, especially through walls or on a crowded 2.4GHz channel
- Someone else downloading or streaming at the same time (bufferbloat)
- An overloaded router or a powerline adapter
- Congestion at your ISP in the evening
The fixes that work for every game
- Use a cable. Wi-Fi adds a few milliseconds and, worse, random spikes whenever a neighbor's network or your microwave interferes. See Wi-Fi vs Ethernet.
- Stop everything else using the line. Cloud backups, game updates (Steam, Battle.net, consoles in rest mode), 4K streams and video calls in the same household. If your ping only goes bad when someone else is online, that is bufferbloat.
- Restart the router and modem. Boring, but consumer routers do degrade after weeks of uptime.
- Turn on QoS or SQM in the router, if it has it. Smart Queue Management (often called “fq_codel” or “CAKE”) is the single best fix for lag that appears under load.
- Pick the closest server region the game lets you choose. Every 1,000 km of fiber adds roughly 10ms of round trip.
- Check the route. If your ping is high only to one region while everything else is fine, your ISP may be routing badly. A gaming VPN (ExitLag (Werbung), WTFast and similar) can help in exactly this case, and only this case. If your own line is the problem, a VPN can't fix it.
Run the Rekt-al Net test to see your jitter. Use the Long mode to catch spikes that only show up every few seconds.