Glossary term
What is p50 / p95 / p99 (50th / 95th / 99th percentile)?
p50 / p95 / p99 stands for 50th / 95th / 99th percentile.
The latency that 50% / 95% / 99% of requests are faster than. Example: p99 = 800 ms means 1 in 100 requests takes longer than 800 ms.
Learn it properly · System DesignLesson 8: Latency, Throughput & Why p99 MattersAn 80 ms average can hide a checkout that freezes for five seconds. Latency, throughput and Little's Law, why queues explode near full utilisation, and why at scale the p99 becomes what most users feel.