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.
Calculations run locally in your browserTool
Example — 850 satisfied · 120 tolerating · 30 frustrated
Apdex score
0.910
(satisfied + tolerating/2) / total
Rating
Good
published Apdex band 0.85–0.93
Frustrated %
3.0%
30 of 1,000 samples
Total samples
1,000
satisfied + tolerating + frustrated
Affiliate disclosure
Uptime, incident, and on-call management. Better Stack provides status pages, incident management, and on-call scheduling for engineering teams.
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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
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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