Every paper size you will ever need — in one reference. This guide covers the ISO A, B, and C series, North American sizes, envelopes, photo formats, and digital pixel dimensions at 72, 96, 150, 300, and 600 DPI.
ISO A Series (ISO 216)
The A series is the most widely used paper format worldwide. Each size is half the area of the previous one, with an aspect ratio of 1:√2.
| Format | mm | cm | inches | Pixels @300 DPI |
|---|---|---|---|---|
| A0 | 841 × 1189 | 84.1 × 118.9 | 33.1 × 46.8 | 9933 × 14043 |
| A1 | 594 × 841 | 59.4 × 84.1 | 23.4 × 33.1 | 7016 × 9933 |
| A2 | 420 × 594 | 42.0 × 59.4 | 16.5 × 23.4 | 4961 × 7016 |
| A3 | 297 × 420 | 29.7 × 42.0 | 11.7 × 16.5 | 3508 × 4961 |
| A4 | 210 × 297 | 21.0 × 29.7 | 8.3 × 11.7 | 2480 × 3508 |
| A5 | 148 × 210 | 14.8 × 21.0 | 5.8 × 8.3 | 1748 × 2480 |
| A6 | 105 × 148 | 10.5 × 14.8 | 4.1 × 5.8 | 1240 × 1748 |
| A7 | 74 × 105 | 7.4 × 10.5 | 2.9 × 4.1 | 874 × 1240 |
| A8 | 52 × 74 | 5.2 × 7.4 | 2.0 × 2.9 | 614 × 874 |
| A9 | 37 × 52 | 3.7 × 5.2 | 1.5 × 2.0 | 437 × 614 |
| A10 | 26 × 37 | 2.6 × 3.7 | 1.0 × 1.5 | 307 × 437 |
ISO B Series (ISO 216)
The B series is used for posters, books, and envelopes. B sizes are defined as the geometric mean between successive A sizes.
| Format | mm | cm | inches | Pixels @300 DPI |
|---|---|---|---|---|
| B0 | 1000 × 1414 | 100.0 × 141.4 | 39.4 × 55.7 | 11811 × 16701 |
| B1 | 707 × 1000 | 70.7 × 100.0 | 27.8 × 39.4 | 8350 × 11811 |
| B2 | 500 × 707 | 50.0 × 70.7 | 19.7 × 27.8 | 5906 × 8350 |
| B3 | 353 × 500 | 35.3 × 50.0 | 13.9 × 19.7 | 4169 × 5906 |
| B4 | 250 × 353 | 25.0 × 35.3 | 9.8 × 13.9 | 2953 × 4169 |
| B5 | 176 × 250 | 17.6 × 25.0 | 6.9 × 9.8 | 2079 × 2953 |
| B6 | 125 × 176 | 12.5 × 17.6 | 4.9 × 6.9 | 1476 × 2079 |
| B7 | 88 × 125 | 8.8 × 12.5 | 3.5 × 4.9 | 1039 × 1476 |
| B8 | 62 × 88 | 6.2 × 8.8 | 2.4 × 3.5 | 732 × 1039 |
| B9 | 44 × 62 | 4.4 × 6.2 | 1.7 × 2.4 | 520 × 732 |
| B10 | 31 × 44 | 3.1 × 4.4 | 1.2 × 1.7 | 366 × 520 |
ISO C Series (Envelopes, ISO 269)
The C series is designed for envelopes. A C4 envelope holds an unfolded A4 sheet; a C5 holds A5, and so on.
| Format | mm | cm | inches | Fits |
|---|---|---|---|---|
| C0 | 917 × 1297 | 91.7 × 129.7 | 36.1 × 51.1 | A0 |
| C1 | 648 × 917 | 64.8 × 91.7 | 25.5 × 36.1 | A1 |
| C2 | 458 × 648 | 45.8 × 64.8 | 18.0 × 25.5 | A2 |
| C3 | 324 × 458 | 32.4 × 45.8 | 12.8 × 18.0 | A3 |
| C4 | 229 × 324 | 22.9 × 32.4 | 9.0 × 12.8 | A4 |
| C5 | 162 × 229 | 16.2 × 22.9 | 6.4 × 9.0 | A5 |
| C6 | 114 × 162 | 11.4 × 16.2 | 4.5 × 6.4 | A6 |
| C7 | 81 × 114 | 8.1 × 11.4 | 3.2 × 4.5 | A7 |
| C8 | 57 × 81 | 5.7 × 8.1 | 2.2 × 3.2 | A8 |
| C9 | 40 × 57 | 4.0 × 5.7 | 1.6 × 2.2 | A9 |
| C10 | 28 × 40 | 2.8 × 4.0 | 1.1 × 1.6 | A10 |
DL envelope: 110 × 220 mm — fits a folded A4 sheet (A4 folded twice = A5, but DL is slightly narrower).
North American Sizes
| Name | inches | mm | Pixels @300 DPI |
|---|---|---|---|
| Letter | 8.5 × 11 | 216 × 279 | 2550 × 3300 |
| Legal | 8.5 × 14 | 216 × 356 | 2550 × 4200 |
| Tabloid / Ledger | 11 × 17 | 279 × 432 | 3300 × 5100 |
| Executive | 7.25 × 10.5 | 184 × 267 | 2175 × 3150 |
| Half Letter | 5.5 × 8.5 | 140 × 216 | 1650 × 2550 |
| Junior Legal | 5 × 8 | 127 × 203 | 1500 × 2400 |
| ANSI A | 8.5 × 11 | 216 × 279 | 2550 × 3300 |
| ANSI B | 11 × 17 | 279 × 432 | 3300 × 5100 |
| ANSI C | 17 × 22 | 432 × 559 | 5100 × 6600 |
| ANSI D | 22 × 34 | 559 × 864 | 6600 × 10200 |
| ANSI E | 34 × 44 | 864 × 1118 | 10200 × 13200 |
US Envelopes
| Name | inches | mm | Use |
|---|---|---|---|
| #10 | 4.125 × 9.5 | 104.8 × 241.3 | Business letters |
| #9 | 3.875 × 8.875 | 98.4 × 225.4 | Personal letters |
| #6¾ | 3.625 × 6.5 | 92.1 × 165.1 | Personal |
| A2 | 4.375 × 5.75 | 111 × 146 | Invitations |
| A6 | 4.75 × 6.5 | 121 × 165 | Photos |
| A7 | 5.25 × 7.25 | 133 × 184 | Invitations |
| A8 | 5.5 × 8.125 | 140 × 206 | Cards |
| A9 | 5.75 × 8.75 | 146 × 222 | Cards |
| A10 | 6 × 9.5 | 152 × 241 | Cards |
Photo Formats
| Name | inches | mm | Pixels @300 DPI |
|---|---|---|---|
| 3R | 3.5 × 5 | 89 × 127 | 1050 × 1500 |
| 4R (4×6) | 4 × 6 | 102 × 152 | 1200 × 1800 |
| 5R (5×7) | 5 × 7 | 127 × 178 | 1500 × 2100 |
| 6R (6×8) | 6 × 8 | 152 × 203 | 1800 × 2400 |
| 8R (8×10) | 8 × 10 | 203 × 254 | 2400 × 3000 |
| 10R (10×12) | 10 × 12 | 254 × 305 | 3000 × 3600 |
| Passport (ID-1) | 1.38 × 1.77 | 35 × 45 | 413 × 531 |
Digital Pixel Dimensions at Common Resolutions
| Format | 72 DPI | 96 DPI | 150 DPI | 300 DPI | 600 DPI |
|---|---|---|---|---|---|
| A4 | 595 × 842 | 794 × 1123 | 1240 × 1754 | 2480 × 3508 | 4961 × 7016 |
| A3 | 842 × 1191 | 1123 × 1587 | 1754 × 2480 | 3508 × 4961 | 7016 × 9933 |
| A5 | 420 × 595 | 559 × 794 | 874 × 1240 | 1748 × 2480 | 3508 × 4961 |
| Letter | 612 × 792 | 816 × 1056 | 1275 × 1650 | 2550 × 3300 | 5100 × 6600 |
| Legal | 612 × 1008 | 816 × 1344 | 1275 × 2100 | 2550 × 4200 | 5100 × 8400 |
| B5 | 499 × 709 | 665 × 945 | 1039 × 1476 | 2079 × 2953 | 4157 × 5906 |
Points and Picas
1 point (pt) = 1/72 inch. 1 pica = 12 points. These are used in typography and print layout.
| Format | Width (pt) | Height (pt) |
|---|---|---|
| A4 | 595.28 | 841.89 |
| Letter | 612 | 792 |
| A5 | 419.53 | 595.28 |
Frequently Asked Questions
What is A4 in pixels at 300 DPI?
2480 × 3508 pixels.
What size is Letter paper in mm?
216 × 279 mm (8.5 × 11 inches).
What is the difference between A4 and Letter?
A4 is 210 × 297 mm; Letter is 216 × 279 mm. A4 is narrower and taller.
What is a C4 envelope?
229 × 324 mm — it holds an unfolded A4 sheet.
What is B5 in inches?
176 × 250 mm = 6.93 × 9.84 inches.
What is 4R photo size?
4 × 6 inches (102 × 152 mm) — the most common photo print size.
How many pixels is 4R at 300 DPI?
1200 × 1800 pixels.
What is the aspect ratio of A4?
1:√2 (approximately 1:1.414).
Conclusion
This reference covers the essential paper sizes for print, design, and digital work. Bookmark it for quick access to A, B, and C series, North American formats, envelopes, photo sizes, and pixel dimensions at every common DPI.