Convert between every standard paper size — ISO A0–A10, B-series, C-series, US Letter / Legal / Tabloid and Japanese JIS — in mm and inches.
| Size | mm | cm | inches | Area (cm²) |
|---|
ISO A-series starts at A0 = 841 × 1189 mm (1 m² area, √2 aspect). Each next size halves the longer dimension. B-series is the geometric mean of consecutive A sizes, and C-series fits A inside (used for envelopes).
The scale ratio is min(B.w/A.w, B.h/A.h) — the largest factor that fits A inside B without cropping. 1 inch = 25.4 mm.
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