A paper size is a standardized sheet format, and this reference lists 69 of them across seven families — with every dimension in millimeters and inches. The international system, ISO 216, builds on a single idea: a height-to-width ratio of √2 (about 1 to 1.414), the only proportion that stays the same when a sheet is halved — fold an A3 in half and you hold exactly two A4s. The physicist Georg Christoph Lichtenberg described the ratio in 1786; Germany standardized it as DIN 476 in 1922, and it became international standard ISO 216 in 1975.
The families run from the everyday to the specialized: the A series and its companions — B for in-between print sizes, C for the envelopes that hold them, RA and SRA for the oversized press sheets they are trimmed from — then the North American world of Letter, Legal, and the ANSI and architectural series, and finally Japan’s larger JIS B series. Photo-print, newspaper, and business-card formats follow separate conventions and are not covered here, and the traditional British imperial names (Foolscap, Crown, Demy) left official use after metrication. The A sizes A0–A10 and the A series itself also appear in the encyclopedia’s A band.
ISO A series
| A0 | ISO 216 A0The base of the A series, 841 × 1,189 mm (33.11 × 46.81 in), defined so its area is exactly one square meter; every smaller A size is made by halving the sheet across its longer side. |
|---|---|
| A1 | ISO 216 A1594 × 841 mm (23.39 × 33.11 in) — half an A0; posters, flip charts, and technical drawings. |
| A2 | ISO 216 A2420 × 594 mm (16.54 × 23.39 in); drawings, small posters, and wall calendars. |
| A3 | ISO 216 A3297 × 420 mm (11.69 × 16.54 in) — exactly two A4s side by side; spreadsheets, diagrams, and small posters. |
| A4 | ISO 216 A4210 × 297 mm (8.27 × 11.69 in) — the world’s standard office paper, reached by halving A0 four times; a sheet of everyday 80 g/m² stock weighs almost exactly 5 grams. |
| A5 | ISO 216 A5148 × 210 mm (5.83 × 8.27 in) — half an A4; notepads, flyers, and small booklets. |
| A6 | ISO 216 A6105 × 148 mm (4.13 × 5.83 in) — the standard international postcard size. |
| A7 | ISO 216 A774 × 105 mm (2.91 × 4.13 in); pocket notebooks and admission tickets. |
| A8 | ISO 216 A852 × 74 mm (2.05 × 2.91 in) — close to playing-card size; labels and vouchers. |
| A9 | ISO 216 A937 × 52 mm (1.46 × 2.05 in); small labels and stamps of the paper world. |
| A10 | ISO 216 A1026 × 37 mm (1.02 × 1.46 in) — the smallest standard A size; a single A0 sheet cuts into 1,024 of them. |
ISO B series
| B0 | ISO 216 B01,000 × 1,414 mm (39.37 × 55.67 in) — exactly one meter wide; each B size is the geometric mean between the two neighboring A sizes, giving printers an in-between set. |
|---|---|
| B1 | ISO 216 B1707 × 1,000 mm (27.83 × 39.37 in); large posters and wall maps. |
| B2 | ISO 216 B2500 × 707 mm (19.69 × 27.83 in); posters and art prints. |
| B3 | ISO 216 B3353 × 500 mm (13.90 × 19.69 in); small posters and newspaper pages in some markets. |
| B4 | ISO 216 B4250 × 353 mm (9.84 × 13.90 in); magazines and larger book formats. |
| B5 | ISO 216 B5176 × 250 mm (6.93 × 9.84 in) — a common book trim size, between A4 and A5. |
| B6 | ISO 216 B6125 × 176 mm (4.92 × 6.93 in); paperbacks and postcards. |
| B7 | ISO 216 B788 × 125 mm (3.46 × 4.92 in) — the ID-card-and-passport neighborhood of the series. |
| B8 | ISO 216 B862 × 88 mm (2.44 × 3.46 in); close to standard playing-card size. |
| B9 | ISO 216 B944 × 62 mm (1.73 × 2.44 in); small labels. |
| B10 | ISO 216 B1031 × 44 mm (1.22 × 1.73 in) — the smallest standard B size. |
ISO C series & the DL envelope
| C0 | ISO C0 envelope917 × 1,297 mm (36.10 × 51.06 in). The C series (defined in ISO 269, withdrawn in 2009 though the sizes remain the worldwide envelope norm) sits between A and B: a C envelope holds the same-numbered A sheet flat. |
|---|---|
| C1 | ISO C1 envelope648 × 917 mm (25.51 × 36.10 in); holds an A1 sheet unfolded. |
| C2 | ISO C2 envelope458 × 648 mm (18.03 × 25.51 in); holds an A2 sheet unfolded. |
| C3 | ISO C3 envelope324 × 458 mm (12.76 × 18.03 in); holds an A3 sheet unfolded. |
| C4 | ISO C4 envelope229 × 324 mm (9.02 × 12.76 in) — the envelope that takes an A4 sheet completely flat; certificates and documents that must not be folded. |
| C5 | ISO C5 envelope162 × 229 mm (6.38 × 9.02 in); takes an A4 folded once (to A5), or an A5 sheet flat. |
| C6 | ISO C6 envelope114 × 162 mm (4.49 × 6.38 in); takes an A4 folded twice (to A6) — the classic small mailing envelope. |
| C7 | ISO C7 envelope81 × 114 mm (3.19 × 4.49 in); small cards and RSVP envelopes. |
| C8 | ISO C8 envelope57 × 81 mm (2.24 × 3.19 in). |
| C9 | ISO C9 envelope40 × 57 mm (1.57 × 2.24 in). |
| C10 | ISO C10 envelope28 × 40 mm (1.10 × 1.57 in) — the smallest C size. |
| DL | DL envelope110 × 220 mm (4.33 × 8.66 in) — the everyday business envelope worldwide; the name comes from the German DIN lang (“DIN long”), and it takes an A4 sheet folded into thirds. |
RA & SRA press sheets
| RA0 | ISO 217 RA0860 × 1,220 mm (33.86 × 48.03 in) — “raw format A”: the untrimmed press sheet slightly larger than A0, so pages can be printed edge to edge and cut down. |
|---|---|
| RA1 | ISO 217 RA1610 × 860 mm (24.02 × 33.86 in); the untrimmed sheet for A1 work. |
| RA2 | ISO 217 RA2430 × 610 mm (16.93 × 24.02 in); the untrimmed sheet for A2 work. |
| SRA0 | ISO 217 SRA0900 × 1,280 mm (35.43 × 50.39 in) — “supplementary raw format A”, with extra margin for full-bleed printing; printed oversize, then trimmed to the finished A size. |
| SRA1 | ISO 217 SRA1640 × 900 mm (25.20 × 35.43 in); the bleed sheet for A1 work. |
| SRA2 | ISO 217 SRA2450 × 640 mm (17.72 × 25.20 in); the bleed sheet for A2 work — a size every commercial printer keeps in stock. |
North American & ANSI sizes
| Letter | US Letter8.5 × 11 in (215.9 × 279.4 mm) — the standard office sheet in the United States, Canada, Mexico, and the Philippines; it is 5.9 mm wider and 17.6 mm shorter than A4. |
|---|---|
| Legal | US Legal8.5 × 14 in (215.9 × 355.6 mm); contracts and other legal documents — the same width as Letter, three inches taller. |
| Tabloid | Tabloid (Ledger)11 × 17 in (279.4 × 431.8 mm) — exactly two Letter sheets; called Ledger when used landscape, and identical to ANSI B. |
| Executive | Executive7.25 × 10.5 in (184.1 × 266.7 mm); a smaller stationery size once common for personal correspondence. |
| Statement | Statement (Half Letter)5.5 × 8.5 in (139.7 × 215.9 mm) — half a Letter sheet; also sold as Half Letter or Memo, common for organizers and invoices. |
| Government Letter | Government Letter8 × 10.5 in (203.2 × 266.7 mm) — the size US federal forms used until the government moved to Letter in the 1980s; still seen in older filing systems. |
| Government Legal | Government Legal8.5 × 13 in (215.9 × 330.2 mm); an in-between legal size, still a common official-form sheet in several countries. |
| ANSI A | ANSI A8.5 × 11 in (215.9 × 279.4 mm) — Letter under its engineering name in the ANSI/ASME Y14.1 series. |
| ANSI B | ANSI B11 × 17 in (279.4 × 431.8 mm). Unlike ISO’s constant √2, the ANSI series alternates between 1:1.29 and 1:1.55 ratios, so enlarging between sizes needs two different scale factors. |
| ANSI C | ANSI C17 × 22 in (431.8 × 558.8 mm); mid-size engineering drawings. |
| ANSI D | ANSI D22 × 34 in (558.8 × 863.6 mm); large engineering drawings. |
| ANSI E | ANSI E34 × 44 in (863.6 × 1,117.6 mm) — the largest sheet in the ANSI engineering series. |
Architectural (Arch) sizes
| Arch A | Arch A9 × 12 in (228.6 × 304.8 mm). The architectural series uses the cleaner 4:3 and 3:2 proportions, which architects preferred to the ANSI ratios. |
|---|---|
| Arch B | Arch B12 × 18 in (304.8 × 457.2 mm); small architectural drawings and presentation sheets. |
| Arch C | Arch C18 × 24 in (457.2 × 609.6 mm); mid-size plans. |
| Arch D | Arch D24 × 36 in (609.6 × 914.4 mm) — the most common size for working architectural drawings in North America. |
| Arch E | Arch E36 × 48 in (914.4 × 1,219.2 mm); full-size architectural plan sheets. |
| Arch E1 | Arch E130 × 42 in (762 × 1,066.8 mm); an intermediate plan size between Arch D and Arch E. |
JIS B series (Japan)
| JIS B0 | JIS P 0138 B01,030 × 1,456 mm (40.55 × 57.32 in). Japan’s B series defines each size as 1.5 times the area of the matching A size — larger than ISO B, whose factor is √2 (about 1.41). |
|---|---|
| JIS B1 | JIS P 0138 B1728 × 1,030 mm (28.66 × 40.55 in); large posters in Japan. |
| JIS B2 | JIS P 0138 B2515 × 728 mm (20.28 × 28.66 in); posters and charts. |
| JIS B3 | JIS P 0138 B3364 × 515 mm (14.33 × 20.28 in); posters and transit advertising. |
| JIS B4 | JIS P 0138 B4257 × 364 mm (10.12 × 14.33 in) — a standard Japanese document and newspaper-insert size. |
| JIS B5 | JIS P 0138 B5182 × 257 mm (7.17 × 10.12 in) — the classic Japanese notebook and textbook size; 6 mm wider and 7 mm taller than ISO B5. |
| JIS B6 | JIS P 0138 B6128 × 182 mm (5.04 × 7.17 in); paperbacks and handbooks. |
| JIS B7 | JIS P 0138 B791 × 128 mm (3.58 × 5.04 in); pocket diaries. |
| JIS B8 | JIS P 0138 B864 × 91 mm (2.52 × 3.58 in); small memo pads. |
| JIS B9 | JIS P 0138 B945 × 64 mm (1.77 × 2.52 in); labels. |
| JIS B10 | JIS P 0138 B1032 × 45 mm (1.26 × 1.77 in) — the smallest JIS B size. |
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