Jitter

What It Means

Jitter measures the variation in packet arrival time, it is calculated as the statistical variance of latency over a stream of packets, typically expressed as a single millisecond value. A connection with 20 ms mean latency but 50 ms jitter (meaning actual packet latencies range widely from 5 ms to 70 ms or more) is noticeably worse for real-time applications than a connection with 40 ms mean latency and 2 ms jitter, because application buffers have to absorb the variation. Jitter above 30 ms degrades video calls visibly (frozen frames, choppy audio), and jitter above 50 ms makes competitive online gaming unplayable (rubberbanding, desync). Technology-specific baselines: fiber typically delivers 1 to 3 ms jitter, cable 5 to 15 ms during normal conditions but can spike to 30 ms or higher during evening peak hours due to shared-medium contention, DSL 10 to 20 ms, fixed wireless 10 to 40 ms, Starlink LEO satellite 5 to 30 ms but with occasional large spikes during satellite handoffs. Most speed test tools (Ookla Speedtest, M-Lab NDT, Netflix Fast.com) measure jitter alongside ping as part of the latency assessment. The FCC Broadband Nutrition Label does not currently require jitter disclosure but does require typical latency. For remote workers, persistent jitter above 20 ms on a cable plan is often a signal that DOCSIS node congestion needs attention from the ISP, and a support ticket referencing specific jitter measurements often leads to a node split or plant upgrade.

Frequently Asked Questions