Statistical process control · in your browser

LimitLine

Control charts, special-cause rules and capability. Paste from Excel or drop a CSV. Nothing is uploaded — every calculation runs on this page.

Analysis tools

Measurements (time order)

One value per line, or separated by commas or spaces. Paste a column from Excel or drop a CSV here.

Subgroups — one per line

Each line is one subgroup (same size, 2–25 values). Paste rows from Excel or drop a CSV.

Chart

Chart Count, sample size — one sample per line

Sample size (constant)

What kind of data do you have? Measurements (length, weight, time, temperature…) Counts (defects, pass/fail items)

How many measurements per sample?

What do you count? Defective items (each item passes or fails) Defects (one item can have several)

Is the sample size or inspected area always the same? Yes, always the same No, it varies

Lower spec (LSL)

Upper spec (USL)

Special-cause rules (Nelson)

Customize charts

Chart title

Measurement and units

Decimal places

Target / nominal

Cpk goal

Chart colors

Chart height

Show ±1σ and ±2σ zone lines Show spec limits on the control chart Normal curve on the histogram First column is a label (date, lot, shift)

Limits from first N points

Exclude from limits

Point notes

Settings are saved in this browser only.

Individuals chart

Moving range chart

Limits and verdict

Signals

Distribution

Scan from image or file

Preview as

Choose a photo, scan or file, drop it here, or paste it (Ctrl+V).
A phone photo of a check sheet, a screenshot, or a PDF, Word, Excel or CSV file.

Table

Choose an image or file to start.

Or paste text from your phone

iPhone: open the photo, press and hold the numbers, Copy. Android: Google Lens → Text → Copy. Paste below.

Check: low confidence or a letter was fixedNot a number

The numbers it reads appear here. Fix any cell before you insert.

1 · Set the scale

value

Log scale

2 · Find the points

Marker size Color match

No dots on the line?

3 · Check

Click a point to remove it; click empty space to add one.

Choose a chart image to start.

Free: 1 scan a day. Pro and Student: 20. Team and Expert: unlimited. "Read numbers" runs on your device; images and files are never uploaded.

Methods: NIST/SEMATECH e-Handbook of Statistical Methods — individuals, X̄-R and X̄-S, c and p charts, capability. Every release is tested against NIST's worked examples. Cp and Cpk on the chart tabs assume a stable, roughly normal process; for skewed data use Capability+. LimitLine calculates statistics; it does not certify a process.