SRE
Apdex Score Calculator
Enter satisfied, tolerating, and frustrated request counts to compute Apdex score (0.0–1.0) and rating band. Runs entirely in your browser — no data is transmitted.
No data is transmitted — everything runs locallyTool
Example — 850 satisfied · 120 tolerating · 1000 total
Apdex Score
0.910
Rating
Good
Satisfied %
85.0%
Tolerating %
12.0%
About this tool
Apdex Score Calculator
The Apdex Score Calculator computes the Application Performance Index from satisfied, tolerating, and frustrated request counts, returning a 0–1 score and rating band (Excellent/Good/Fair/Poor/Unacceptable).
• Establish an Apdex baseline before setting SLO targets for a new service
• Calculate Apdex from a monitoring report for an incident post-mortem
• Determine whether a latency degradation crosses the SLO reporting threshold
• Translate raw P99 request counts into an Apdex score for stakeholder reporting
Affiliate disclosure
Uptime, incident, and on-call management. Better Stack provides status pages, incident management, and on-call scheduling for engineering teams.
View options with Better Stack
External site · Independent provider · We may receive a commission · Not a recommendation
FAQ
What does this tool tell you?
The Apdex Score Calculator computes the Application Performance Index from satisfied, tolerating, and frustrated request counts, returning a 0–1 score and rating band (Excellent/Good/Fair/Poor/Unacceptable).
What affects the result most?
Apdex score = (Satisfied + 0.5 × Tolerating) / Total Requests. Thresholds: Excellent ≥0.94, Good 0.85–0.93, Fair 0.70–0.84, Poor 0.50–0.69, Unacceptable <0.50. T (satisfaction threshold) defines the toleration multiplier (0.5) and frustration boundary (4×T).
How should I use the result?
The calculation is deterministic — the same inputs always produce the same output — so the most useful workflow is to vary one input at a time and see which factor moves the result most. That tells you where to focus your attention before committing to a decision.
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