Paper size charts: A, B, C and K series
Complete A0–A10, B0–B10, C0–C10 and Chinese K-sheet paper sizes, with millimetre, centimetre, inch and pixel conversions for printing and design.
A-series paper
ISO A-series sizes from A0 to A10, based on a 1:√2 aspect ratio and a 1 m² A0 sheet.
B-series paper
ISO B-series sizes from B0 to B10, used for posters, books and envelopes.
C-series envelopes
C-series envelope sizes designed to hold A-series sheets without folding or with a single fold.
Chinese K-sheet paper
Chinese full-sheet, 4K, 8K, 16K, 32K and 64K paper sizes, common in books and notebooks.
All size charts
| Category | Size (cm) | Area | Common uses |
|---|---|---|---|
| A4 | 21 × 29.7 cm | 623.7 cm² | Office documents, Letters and reports, Everyday printing |
| A3 | 29.7 × 42 cm | 1,247.4 cm² | Office documents, Letters and reports, Everyday printing |
| A5 | 14.8 × 21 cm | 310.8 cm² | Office documents, Letters and reports, Everyday printing |
| B5 | 17.6 × 25 cm | 440 cm² | Posters and books, Envelopes and folders, Large-format printing |
| C4 | 22.9 × 32.4 cm | 741.96 cm² | Envelopes, Cards and invitations, Mailings |
| C5 | 16.2 × 22.9 cm | 370.98 cm² | Envelopes, Cards and invitations, Mailings |
| 16K (standard) | 18.5 × 26 cm | 481 cm² | Chinese books, Booklets, Notebooks |
| 8K (standard) | 26 × 38 cm | 988 cm² | Chinese books, Booklets, Notebooks |
📄 A-series paper
ISO A-series sizes from A0 to A10, based on a 1:√2 aspect ratio and a 1 m² A0 sheet.
| Category | Size (cm) | Area | Common uses |
|---|---|---|---|
| A0 | 84.1 × 118.9 cm | 9,999.49 cm² | Office documents, Letters and reports, Everyday printing |
| A1 | 59.4 × 84.1 cm | 4,995.54 cm² | Office documents, Letters and reports, Everyday printing |
| A2 | 42 × 59.4 cm | 2,494.8 cm² | Office documents, Letters and reports, Everyday printing |
| A3 | 29.7 × 42 cm | 1,247.4 cm² | Office documents, Letters and reports, Everyday printing |
| A4 | 21 × 29.7 cm | 623.7 cm² | Office documents, Letters and reports, Everyday printing |
| A5 | 14.8 × 21 cm | 310.8 cm² | Office documents, Letters and reports, Everyday printing |
| A6 | 10.5 × 14.8 cm | 155.4 cm² | Office documents, Letters and reports, Everyday printing |
| A7 | 7.4 × 10.5 cm | 77.7 cm² | Office documents, Letters and reports, Everyday printing |
| A8 | 5.2 × 7.4 cm | 38.48 cm² | Office documents, Letters and reports, Everyday printing |
| A9 | 3.7 × 5.2 cm | 19.24 cm² | Office documents, Letters and reports, Everyday printing |
| A10 | 2.6 × 3.7 cm | 9.62 cm² | Office documents, Letters and reports, Everyday printing |
📘 B-series paper
ISO B-series sizes from B0 to B10, used for posters, books and envelopes.
| Category | Size (cm) | Area | Common uses |
|---|---|---|---|
| B0 | 100 × 141.4 cm | 14,140 cm² | Posters and books, Envelopes and folders, Large-format printing |
| B1 | 70.7 × 100 cm | 7,070 cm² | Posters and books, Envelopes and folders, Large-format printing |
| B2 | 50 × 70.7 cm | 3,535 cm² | Posters and books, Envelopes and folders, Large-format printing |
| B3 | 35.3 × 50 cm | 1,765 cm² | Posters and books, Envelopes and folders, Large-format printing |
| B4 | 25 × 35.3 cm | 882.5 cm² | Posters and books, Envelopes and folders, Large-format printing |
| B5 | 17.6 × 25 cm | 440 cm² | Posters and books, Envelopes and folders, Large-format printing |
| B6 | 12.5 × 17.6 cm | 220 cm² | Posters and books, Envelopes and folders, Large-format printing |
| B7 | 8.8 × 12.5 cm | 110 cm² | Posters and books, Envelopes and folders, Large-format printing |
| B8 | 6.2 × 8.8 cm | 54.56 cm² | Posters and books, Envelopes and folders, Large-format printing |
| B9 | 4.4 × 6.2 cm | 27.28 cm² | Posters and books, Envelopes and folders, Large-format printing |
| B10 | 3.1 × 4.4 cm | 13.64 cm² | Posters and books, Envelopes and folders, Large-format printing |
✉️ C-series envelopes
C-series envelope sizes designed to hold A-series sheets without folding or with a single fold.
| Category | Size (cm) | Area | Common uses |
|---|---|---|---|
| C0 | 91.7 × 129.7 cm | 11,893.49 cm² | Envelopes, Cards and invitations, Mailings |
| C1 | 64.8 × 91.7 cm | 5,942.16 cm² | Envelopes, Cards and invitations, Mailings |
| C2 | 45.8 × 64.8 cm | 2,967.84 cm² | Envelopes, Cards and invitations, Mailings |
| C3 | 32.4 × 45.8 cm | 1,483.92 cm² | Envelopes, Cards and invitations, Mailings |
| C4 | 22.9 × 32.4 cm | 741.96 cm² | Envelopes, Cards and invitations, Mailings |
| C5 | 16.2 × 22.9 cm | 370.98 cm² | Envelopes, Cards and invitations, Mailings |
| C6 | 11.4 × 16.2 cm | 184.68 cm² | Envelopes, Cards and invitations, Mailings |
| C7 | 8.1 × 11.4 cm | 92.34 cm² | Envelopes, Cards and invitations, Mailings |
| C8 | 5.7 × 8.1 cm | 46.17 cm² | Envelopes, Cards and invitations, Mailings |
| C9 | 4 × 5.7 cm | 22.8 cm² | Envelopes, Cards and invitations, Mailings |
| C10 | 2.8 × 4 cm | 11.2 cm² | Envelopes, Cards and invitations, Mailings |
📰 Chinese K-sheet paper
Chinese full-sheet, 4K, 8K, 16K, 32K and 64K paper sizes, common in books and notebooks.
| Category | Size (cm) | Area | Common uses |
|---|---|---|---|
| Full sheet (standard) | 78.1 × 108.6 cm | 8,481.66 cm² | Chinese books, Booklets, Notebooks |
| Full sheet (large) | 88.9 × 119.4 cm | 10,614.66 cm² | Chinese books, Booklets, Notebooks |
| Double sheet (standard) | 53 × 76 cm | 4,028 cm² | Chinese books, Booklets, Notebooks |
| Double sheet (large) | 59 × 88 cm | 5,192 cm² | Chinese books, Booklets, Notebooks |
| 4K (standard) | 38 × 53 cm | 2,014 cm² | Chinese books, Booklets, Notebooks |
| 4K (large) | 44 × 59 cm | 2,596 cm² | Chinese books, Booklets, Notebooks |
| 8K (standard) | 26 × 38 cm | 988 cm² | Chinese books, Booklets, Notebooks |
| 8K (large) | 29.5 × 44 cm | 1,298 cm² | Chinese books, Booklets, Notebooks |
| 16K (standard) | 18.5 × 26 cm | 481 cm² | Chinese books, Booklets, Notebooks |
| 16K (large) | 21 × 28.5 cm | 598.5 cm² | Chinese books, Booklets, Notebooks |
| 32K (standard) | 13 × 18.5 cm | 240.5 cm² | Chinese books, Booklets, Notebooks |
| 32K (large) | 14.5 × 21 cm | 304.5 cm² | Chinese books, Booklets, Notebooks |
| 64K (standard) | 9.2 × 13 cm | 119.6 cm² | Chinese books, Booklets, Notebooks |
Paper sizes · Good to know
ISO A-series paper uses a 1:√2 aspect ratio: each size is half the area of the previous one, so A4 (210 × 297 mm) folds neatly down to A5 and enlarges to A3.
B-series paper is used for posters, books and envelopes; C-series envelopes are sized so an A4 sheet folds to fit a C5 envelope. Chinese K-sheet sizes (16K, 8K, 32K) remain common in books and notebooks.
Paper sizes · FAQ
What size is A4 paper?
A4 is 210 × 297 mm (21 × 29.7 cm, 8.27 × 11.69 in).
How many A4 sheets fit on A3?
Two: A3 is 297 × 420 mm, exactly twice the area of A4.
What is the difference between A4 and 16K?
A4 is 210 × 297 mm; 16K paper is about 195 × 270 mm (standard) or 210 × 285 mm (large), slightly smaller than A4.
Which paper size is used for photos?
Photos usually use 4R (102 × 152 mm) or A6/A5 photo paper; see the photo sizes section.