Work out apdex score instantly with clear inputs, formula shown and shareable results.
Apdex condenses a latency distribution into one number between 0 and 1 by counting satisfied requests fully, tolerating requests at half, and frustrated requests not at all. The frustration boundary is fixed at four times the satisfaction threshold. Its value is comparability across services; its weakness is that the score depends entirely on the threshold you chose, so it must always be quoted with T.
Apdex
Apdex(T) = (satisfied + tolerating / 2) / total; tolerating = requests between T and 4T; frustrated = requests above 4T
From user expectation for the interaction, not from current performance. Setting T to your existing p90 guarantees a flattering score that never improves.
It is less fashionable than SLO-based measurement, which expresses the same idea with an explicit target and error budget. Apdex remains useful as a single trend line for stakeholders.