One widget holding a chart for every range you sell, with a button per chart
Centimetres and inches, switched by the shopper and converted from your figures
Three charts free for ever, with every feature switched on — not a trial
A real accessible table per chart, readable at 320px with the size column pinned
A shop that sells coats, trousers and boots needs three size charts, not one. Size Chart Pro holds them in a single widget: the shopper presses the chart they need and reads it there.
You build each chart from your own stock. One row per size, one column per measurement, up to 40 sizes and 8 measurements in each, and up to 12 charts.
Each chart keeps the unit you measured it in, so coats in centimetres and boot lengths in inches can sit side by side. The shopper gets one switch for all of them. Conversion happens at display time from your original figures, which are never overwritten.
Every chart is a real HTML table with a caption naming it and row and column headers, so a screen reader reads "Chest, EU 42, 96". On a narrow screen the table scrolls sideways, not the page, with the size column pinned. Twelve languages; your labels stay as typed.
Plainly: you type every measurement. The app does not recommend a size, does not measure anybody, and does not read sizes from Stores product options, so no chart is pre-filled and none is applied by collection. Nothing is collected from shoppers. Three charts are free for ever with every feature on; Pro is for a fourth and beyond.