Advanced – Non-Functional Testing
Percentile Latency (p50/p95/p99) – ISTQB Definition
Last Updated: July 12, 2026 · SoftwareTestPilot QA Team
Official ISTQB Definition
Latency measurements at specific percentiles indicating the response time below which a given percentage of requests fall.
In simple words
p95 = 95% of requests are faster than this number.
Exam tip
Percentiles reveal tail latency; averages hide the worst user experience.
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