How do you know when a process has really changed versus just wobbled? Statistical process control draws the line at three sigma — and watches for breaches.
SPC Control ChartLive
in control or not?
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Statistical process control watches a process over time against control limits set at three standard deviations from the target. Points inside are normal random variation — leave them alone. A point beyond the limits, or a run trending one way, signals a real change worth investigating. Nudge the process shift and watch points breach the limits.
Reading this result: The process is centered on target: points scatter randomly inside the ±3σ limits, so every point is just noise — reacting now would only add variation (tampering).
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How it works
A control chart plots a process measurement over time against a center line and control limits set at three standard deviations. Points within the limits reflect normal random variation and should be left alone; a point beyond them, or a sustained run, signals a genuine shift worth investigating. Nudge the process and watch points breach the limits — the foundation of quality monitoring.
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The math, the assumptions, real-world uses, or a code translation — explained for this exact simulation.
Yes. SPC Control Chart runs entirely in your browser using your device's own compute, so local use is free forever. You only pay Compute Tokens if you scale a job to the cloud.
Do I need to install anything?▾
No. Everything runs client-side in a modern browser — no downloads, no license, no account required to start.
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How accurate are the results?▾
The solver uses established numerical methods, but results are for research and educational purposes and should be validated against experiment or professional review before you rely on them.