Source: https://uptimeify.io/resources/platform-and-support/glossary/percentile

# Percentile (p95 / p99)

> A percentile describes the value below which a given share of measurements fall: p95 latency is the response time that 95% of requests come in under.

Averages hide bad experiences; percentiles expose them. p95 and p99 reveal the slow tail that real users feel, which is why SLOs and performance targets are usually expressed as percentiles rather than means.