What Is Jitter? How Inconsistent Delay Affects Streaming
What jitter actually means, how it's different from latency and packet loss, and why an inconsistent connection can cause problems even with good average speed.
Jitter is variation in delay over time — not the delay itself (latency), and not dropped data (packet loss), but how consistently data arrives. A connection with high jitter delivers data at uneven intervals, which can cause stutters or glitches even when average speed and latency both look fine on paper.
Key Takeaways
- Jitter measures how much delay varies over time, not the delay itself.
- A connection can have low latency but high jitter, or vice versa — they're independent measurements.
- High jitter can cause stutters even when your average speed test result looks perfectly healthy.
- Jitter is often caused by network congestion or an unstable Wi-Fi connection.
- Wired connections generally produce more consistent timing — and therefore lower jitter — than Wi-Fi.
Jitter is the least understood of the three network-timing concepts that affect streaming — here's how it's genuinely different from latency and packet loss, both covered in their own dedicated guides.
What Is Jitter?
Jitter is the variation in delay between data packets arriving at your device. If packets normally arrive every 20 milliseconds but sometimes take 15ms and other times 40ms, that inconsistency is jitter — distinct from the average delay itself, which is latency.
Jitter vs Latency vs Packet Loss
These three concepts are related but measure different things: latency is how long data takes to arrive on average, jitter is how much that timing varies, and packet loss is data that never arrives at all. A connection can have any combination of these — low latency with high jitter, for example, or the reverse.
How Jitter Affects Streaming
Streaming apps buffer a small amount of data in advance specifically to smooth out minor timing variations. High jitter can exceed what that buffer can absorb, leading to brief stutters or glitches even when your average connection speed and latency both test normally.
What Causes Jitter?
- Network congestion, where inconsistent traffic loads cause uneven delivery timing.
- Wi-Fi instability, which is inherently less consistent than a wired connection.
- Router or network hardware struggling under variable load.
- Multiple devices competing for bandwidth at unpredictable times.
How to Reduce Jitter
A wired Ethernet connection generally produces far more consistent timing than Wi-Fi, directly reducing jitter — see our Wi-Fi vs Ethernet comparison. Reducing simultaneous network usage and addressing Wi-Fi interference also help stabilize timing consistency.
Frequently Asked Questions
"Lag" is a general term people use loosely for several different issues — jitter specifically refers to inconsistent delay timing, which is only one possible cause of what people commonly call lag.
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