Jitter is the inconsistency in how long it takes data packets to travel from one point to a network to another. While latency measures the average delay, jitter measures how much that delay varies from packet to packet.
In a stable network, packets arrive at regular intervals. With jitter, some packets arrive quickly whilst others are delayed, creating an uneven flow of data. This irregularity disrupts real-time activities that depend on smooth, predictable data delivery.
Common causes of jitter include network congestion, electromagnetic interference, poor router placement, and overloaded devices. A Wi-Fi connection far from your router tends to have higher jitter than a wired Ethernet connection in the same room.
Real-world impact: During a video call, high jitter causes the other person's voice to stutter or sound robotic, or their video freezes briefly before catching up. In online gaming, jitter makes opponents appear to teleport rather than move smoothly. Streaming services buffer more frequently when jitter is high.
When buying a broadband package or router, look for providers and devices that advertise low and stable jitter figures. Wired connections almost always offer lower jitter than wireless. If you play competitive online games or use your connection for professional video conferencing, minimising jitter should be a priority alongside achieving low latency and high bandwidth.