# What does p95 latency mean when a vendor quotes it?

p95 latency is the time the slowest one in twenty requests takes. Averages hide those: a system that answers in half a second most of the time and eight seconds occasionally has a fine average and an unusable feel. The tail is what users remember, and it is what decides whether they keep the habit.

Also called: 95th percentile latency, tail latency
Checked: 2026-09-27

In one line

The slowest 1 in 20. Averages hide exactly what users notice.

## Why it matters to you

The number is only meaningful with three things attached: what was being measured, under what load, and on what date. A p95 from a laptop on office wifi with one user is not a number about production.

It also has to be measured, because a feeling is not a percentile. OCTYN publishes Mooney's voice time as under five seconds end to end, and says plainly that it is a demonstrated wall-clock time from screen recordings on a Samsung S23 over a live network, not a p95, because per-stage timing is not instrumented in the app. Instrumenting it is the first thing that project's own write-up says it would do differently.

If a vendor quotes you a p95 and cannot say what date it was captured on, it is a feeling with a decimal point.

## Where it turns up in something we run

- Voice to saved row is under five seconds, demonstrated on a Samsung S23 over a live network as a wall-clock time, not an instrumented p95 (recorded 2026-09-14, [Mooney](https://octyn.co/casestudies/mooney))
- p95 voice latency is not instrumented in the app, and is named as a gap, with no number estimated in its place (recorded 2026-09-14, [Mooney](https://octyn.co/casestudies/mooney))

## Next to this

- [Observability](https://octyn.co/glossary/observability)
- [Rate limiting](https://octyn.co/glossary/rate-limiting)

## Argued out at length

- [What production ready means for an AI system](https://octyn.co/compare/production-ready-ai-system)
- [A glued workflow versus a built system at 10,000 runs a month](https://octyn.co/compare/glued-workflow-vs-built-system)

## Related

- [What production ready means for an AI system](https://octyn.co/compare/production-ready-ai-system)
- [Observability](https://octyn.co/glossary/observability)
- [The Consult](https://octyn.co/consult)

Canonical: https://octyn.co/glossary/p95-latency