Redmoon Converters Converta entre todos os tamanhos de papel padrão — ISO A0–A10, série B, série C, US Letter / Legal / Tabloid e JIS japonês — em mm e polegadas.
| Tamanho | mm | cm | polegadas | Área (cm²) |
|---|
A série ISO A começa em A0 = 841 × 1189 mm (área de 1 m², proporção √2). Cada tamanho seguinte reduz a dimensão maior pela metade. A série B é a média geométrica de tamanhos A consecutivos, e a série C encaixa o A dentro (usada em envelopes).
A proporção de escala é min(B.w/A.w, B.h/A.h) — o maior fator que encaixa A dentro de B sem cortar. 1 polegada = 25.4 mm.
Two dropdowns, a fifty-entry lookup table and one ratio. The list holds ISO A0–A10, ISO B0–B10, ISO C0–C10, JIS B0–B10 and six US sizes — Letter, Legal, Tabloid, Executive, Statement and Ledger — all stored in millimetres. Scale A → B is min(B.width ÷ A.width, B.height ÷ A.height) × 100, the largest uniform reduction that fits A entirely inside B. A4 onto US Letter comes out at 94.1%.
Order matters, because A is the source and B is the destination; swapping the two gives a different percentage. The table underneath prints both sizes in millimetres, centimetres, inches at 25.4 mm to the inch, and area in square centimetres, which is the quickest way to see A-series areas halving step by step down from A0's one square metre. The defaults are A4 against US Letter, the comparison most people arrive for.
The percentage is a geometric fit, not a print setting. It ignores your printer's unprintable margin, so scaling A4 artwork to exactly 94.1% on Letter can still clip at the edges — most drivers quietly apply their own shrink on top. The dimensions are the published whole-millimetre values, themselves rounded from the underlying √2 geometry, and every size is listed portrait except US Ledger, stored as 431.8 × 279.4 mm landscape.
94.1%, which is what the tool returns with A4 as size A and US Letter as size B. Going the other way, Letter onto A4, gives 97.3%. Both are fit-to-page factors that keep the entire page visible without cropping anything.
A4 is narrower and taller: 210 × 297 mm against 215.9 × 279.4 mm. By area A4 wins, 623.7 cm² to 603.2 cm². Because the mismatch runs in both directions, neither prints on the other without some scaling.
They are not the same sheet. ISO B5 is 176 × 250 mm, defined as the geometric mean of A4 and A5. JIS B5 is 182 × 257 mm, derived from a larger area rule used in Japan. Both appear in the dropdown.
C4 at 229 × 324 mm takes an unfolded A4 sheet, C5 at 162 × 229 mm takes A4 folded once, and C6 at 114 × 162 mm takes it folded twice. The whole C-series is dimensioned to swallow its matching A size.
A0 is 841 × 1189 mm, one square metre at a √2 aspect ratio. Halving the long side gives each next size down, all the way to A10 at 26 × 37 mm, and the ratio is preserved so scaling between them never distorts proportions.
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