What is latency?
Latency is the time it takes for a piece of data to travel from your device to a server and back again, the round-trip time. It is measured in milliseconds. Even though data travels at close to the speed of light, the distances involved, the number of network hops the data makes, and the processing time at each hop all add up to a measurable delay.
What is ping?
Ping is a specific measurement of latency, the result you see when you run a speed test. In everyday conversation, ping and latency are used interchangeably. Technically, ping is the measurement tool and latency is what it measures.
What do the numbers actually mean?
Under 10ms is excellent and basically imperceptible. 10-30ms is very good and all real-time applications work comfortably. 30-60ms is good and noticeable only in highly competitive gaming. 60-100ms is acceptable for casual use but video calls start to feel slightly stilted. 100-200ms is poor with obvious delays in video calls and games are impaired. Over 200ms is very poor with interactions feeling sluggish.
What causes high latency?
Physical distance to the server. The type of connection, with full fibre generally having lower latency than copper. WiFi adds variable latency compared to ethernet. Network congestion at peak times.
