Reference Chart

Paper Size Chart

Q: What is US Legal paper size?

US Legal measures 8.5 x 14 inches (216 x 356 mm). It is the same width as Letter but 3 inches taller. Used for legal contracts and some government documents in the US, Canada, and the Philippines.

Q: What is the largest paper size?

In the ISO A series, A0 is the largest standard size at 841 x 1189 mm (33.1 x 46.8 inches). 2A0 (1189 x 1682 mm) and 4A0 (1682 x 2378 mm) exist as non-standard extensions. ANSI E (34 x 44 inches) and ARCH E1 (30 x 42 inches) are the largest in US engineering and architectural systems.

Q: How does the A series doubling work?

Each A size is exactly half the area of the size above it (cut along the longer side). A0 = 1 square meter. A1 = half of A0. A2 = half of A1, and so on. All A sizes share an aspect ratio of 1:√2 (about 1:1.414), so scaling between sizes preserves proportions.

Q: What size envelope fits A4 paper?

A4 paper fits a C4 envelope unfolded (229 x 324 mm). Folded once, A4 fits a C5 envelope (162 x 229 mm). Folded twice into thirds, A4 fits a DL envelope (110 x 220 mm), the standard business envelope outside North America.

Q: What size is Tabloid paper?

US Tabloid (also called Ledger when oriented landscape) measures 11 x 17 inches (279 x 432 mm). It is exactly twice the area of US Letter. Used for newspapers, posters, blueprints, and large spreadsheets.

Every paper size you'll actually encounter, in one place. ISO A series (A0 through A10, including the global standard A4), B and C series for posters and envelopes, North American sizes (Letter, Legal, Tabloid), photo print dimensions, and book/poster trim sizes. All dimensions given in millimeters, inches, and pixels at 300 DPI.

ISO A Series Paper Sizes

The international standard. Used in virtually every country except the United States, Canada, and parts of the Philippines. The defining property: each size is exactly half the area of the size above it, and the aspect ratio (1:√2) stays constant.

Size	Millimeters	Inches	Pixels @ 300 DPI	Common Use
A0	841 × 1189 mm	33.1 × 46.8 in	9933 × 14043	Posters, technical drawings
A1	594 × 841 mm	23.4 × 33.1 in	7016 × 9933	Posters, flip charts
A2	420 × 594 mm	16.5 × 23.4 in	4961 × 7016	Drawings, diagrams, posters
A3	297 × 420 mm	11.7 × 16.5 in	3508 × 4961	Drawings, double-page spreads, presentations
A4	210 × 297 mm	8.27 × 11.69 in	2480 × 3508	Letters, magazines, brochures (worldwide standard)
A5	148 × 210 mm	5.83 × 8.27 in	1748 × 2480	Notepads, planners, half-page flyers
A6	105 × 148 mm	4.13 × 5.83 in	1240 × 1748	Postcards, index cards
A7	74 × 105 mm	2.91 × 4.13 in	874 × 1240	Small notes, tickets
A8	52 × 74 mm	2.05 × 2.91 in	614 × 874	Business cards (some markets), playing cards
A9	37 × 52 mm	1.46 × 2.05 in	437 × 614	Mini cards, stamps
A10	26 × 37 mm	1.02 × 1.46 in	307 × 437	Postage stamps, labels

ISO B Series

B sizes sit between consecutive A sizes. Used mostly for posters, books, passports, and envelopes. Less common in office use than A series.

Size	Millimeters	Inches	Use
B0	1000 × 1414 mm	39.4 × 55.7 in	Large posters, banners
B1	707 × 1000 mm	27.8 × 39.4 in	Posters
B2	500 × 707 mm	19.7 × 27.8 in	Posters, calendars
B3	353 × 500 mm	13.9 × 19.7 in	Newspaper sheets, posters
B4	250 × 353 mm	9.8 × 13.9 in	Newspapers, large books
B5	176 × 250 mm	6.9 × 9.8 in	Books, magazines
B6	125 × 176 mm	4.9 × 6.9 in	Books, passports (B7 actually)
B7	88 × 125 mm	3.5 × 4.9 in	Passports
B8	62 × 88 mm	2.4 × 3.5 in	Playing cards (some)

ISO C Series (Envelopes)

C sizes are designed for A-series paper. A piece of paper sized An fits in an envelope sized Cn unfolded.

Size	Millimeters	Inches	Fits
C4	229 × 324 mm	9.0 × 12.8 in	A4 unfolded
C5	162 × 229 mm	6.4 × 9.0 in	A4 folded once, or A5
C6	114 × 162 mm	4.5 × 6.4 in	A4 folded twice, or A6 unfolded
DL	110 × 220 mm	4.3 × 8.7 in	A4 folded into thirds (standard business)

US / North American Paper Sizes

The American standard used in the US, Canada, parts of Mexico, and the Philippines. Defined by the American National Standards Institute (ANSI) and not derived from ISO sizes.

Size	Inches	Millimeters	ANSI	Use
Letter	8.5 × 11	216 × 279 mm	ANSI A	Standard office paper, US
Legal	8.5 × 14	216 × 356 mm	—	Legal contracts, government
Tabloid / Ledger	11 × 17	279 × 432 mm	ANSI B	Newspapers, posters, spreadsheets
ANSI C	17 × 22	432 × 559 mm	ANSI C	Engineering drawings
ANSI D	22 × 34	559 × 864 mm	ANSI D	Engineering drawings
ANSI E	34 × 44	864 × 1118 mm	ANSI E	Large engineering drawings
Junior Legal	5 × 8	127 × 203 mm	—	Legal pads, half-size legal
Half Letter / Statement	5.5 × 8.5	140 × 216 mm	—	Memos, small flyers
Executive	7.25 × 10.5	184 × 267 mm	—	Executive stationery
Government Letter	8 × 10.5	203 × 267 mm	—	Some US gov agencies

Architectural (ARCH) Sizes

Used by architects and designers in North America. Different aspect ratios from ANSI sizes (4:3 and 3:2).

Size	Inches	Millimeters
ARCH A	9 × 12	229 × 305 mm
ARCH B	12 × 18	305 × 457 mm
ARCH C	18 × 24	457 × 610 mm
ARCH D	24 × 36	610 × 914 mm
ARCH E	36 × 48	914 × 1219 mm
ARCH E1	30 × 42	762 × 1067 mm

Photo Print Sizes

Standard photo printing sizes in the US (inches) and internationally (mm). Aspect ratios noted for cropping.

Size	Inches	Millimeters	Aspect	Use
Wallet	2.5 × 3.5	64 × 89 mm	5:7	Wallet, ID
3R	3.5 × 5	89 × 127 mm	5:7	Standard small print
4R / 4x6	4 × 6	102 × 152 mm	2:3	Most common consumer print
5R / 5x7	5 × 7	127 × 178 mm	5:7	Framed photos
6R / 6x8	6 × 8	152 × 203 mm	3:4	Framed prints
8R / 8x10	8 × 10	203 × 254 mm	4:5	Portrait prints, standard frame
11x14	11 × 14	279 × 356 mm	11:14	Fine art prints
16x20	16 × 20	406 × 508 mm	4:5	Wall prints, posters
20x24	20 × 24	508 × 610 mm	5:6	Large wall prints
24x36	24 × 36	610 × 914 mm	2:3	Standard poster

Common US Envelope Sizes

Size	Inches	Fits
#6 3/4	3.625 × 6.5	Letter folded in thirds (small)
#9	3.875 × 8.875	Reply envelope (fits inside #10)
#10	4.125 × 9.5	Letter folded in thirds (US business standard)
A2	4.375 × 5.75	Small invitations, cards
A7	5.25 × 7.25	5x7 cards, invitations
A9	5.75 × 8.75	Half-letter
9 x 12 Booklet	9 × 12	Letter unfolded, photos
10 x 13 Catalog	10 × 13	Catalogs, magazines

Book Trim Sizes

Type	Inches	Use
Mass Market Paperback	4.25 × 6.87	Mass-market fiction
Trade Paperback	5.5 × 8.5	Most trade paperback fiction
Digest	5.5 × 8.5	Some non-fiction, journals
US Trade	6 × 9	Most non-fiction, hardcovers
Royal	6.14 × 9.21	Academic, UK trade
Crown Quarto	7.44 × 9.68	Textbooks, illustrated non-fiction
Letter / 8.5 x 11	8.5 × 11	Workbooks, manuals, photo books

Paper Sizes Guide

The ISO 216 Standard (A, B, C Series)

ISO 216 was published in 1975 based on a German DIN standard (DIN 476, 1922). It defines paper sizes by the rule that each size is half the area of the previous one, with the long side cut in half to produce the next. All sizes share a 1:√2 aspect ratio (~1:1.414), which is preserved when you fold or scale between sizes. This is uniquely useful: a document designed for A4 can be printed on A5 or A3 without distortion. The standard is used by every country except the US, Canada, and (partially) the Philippines.

Why the US Uses Letter and Legal Instead

US Letter (8.5 x 11) predates the ISO standard and was formalized by the Reagan administration in 1980 for federal use. The historical origin is debated: theories include the size of the molds used in early American paper mills, dimensions chosen to fit a specific number of pages per ream, or simply legacy from British colonial paper sizes. Legal (8.5 x 14) was adopted for longer legal documents that needed more lines per page without breaking onto a second sheet.

The downside of US sizes: they don't have a consistent aspect ratio, so scaling between them distorts the layout. There's no clean "half a Letter" equivalent the way A5 is exactly half an A4.

How to Choose Between A4 and Letter

If your audience is in the US, Canada, or the Philippines: use Letter (8.5 x 11)
If your audience is anywhere else: use A4 (210 x 297 mm)
For international audiences mixed across both: A4 is the safer choice, since most US printers can print to A4-like sizes, and international printers can't always handle Letter
For email PDFs and digital reading: A4 is increasingly the global default

Pixels, DPI, and Print Quality

When designing for print, image resolution must be high enough that pixels are not visible at viewing distance. The industry standard is 300 DPI (dots per inch) for high-quality print. Lower resolutions can work for large posters viewed from a distance.

Use Case	DPI	A4 Pixel Size
Professional print	300 DPI	2480 × 3508 px
Home printing (acceptable)	150 DPI	1240 × 1754 px
Large poster (viewed from distance)	100 DPI	827 × 1169 px
Web/screen viewing only	72 DPI	595 × 842 px

Bleed and Safe Areas for Print

When designing for professional print, add bleed (artwork extending past the trim line) so the cutter has tolerance. Standard bleed is 3 mm (1/8 inch) per side. Keep important content (text, faces, logos) at least 5 mm (3/16 inch) inside the trim line, in the "safe area." For A4 with full bleed, your design canvas should be 216 x 303 mm (210+3+3 x 297+3+3).

Frequently Asked Questions

What size is A4 paper?

A4 paper measures 210 x 297 millimeters or 8.27 x 11.69 inches. It is the standard letter-equivalent in most countries outside North America.

What is the difference between A4 and US Letter?

US Letter is 8.5 x 11 inches (216 x 279 mm). A4 is 8.27 x 11.69 inches (210 x 297 mm). A4 is narrower and taller. They are not interchangeable; documents formatted for one often have margin issues when printed on the other.

What size is A3 paper?

A3 paper measures 297 x 420 millimeters or 11.69 x 16.54 inches. It is exactly twice the area of A4.

What is US Legal paper size?

US Legal measures 8.5 x 14 inches (216 x 356 mm). Same width as Letter but 3 inches taller. Used for legal contracts and some government documents.

What is the largest paper size?

In the ISO A series, A0 at 841 x 1189 mm (33.1 x 46.8 in) is the largest standard size. 2A0 and 4A0 exist as non-standard extensions. ANSI E (34 x 44 in) is the largest US engineering size.

How does the A series doubling work?

Each A size is exactly half the area of the size above it. A0 = 1 square meter. A1 = half of A0. A2 = half of A1, and so on. All A sizes share an aspect ratio of 1:√2.

What size is a standard photo print?

Standard photo print sizes in the US are 4x6, 5x7, and 8x10 inches. 4x6 is the most common consumer size. 8x10 is typical for framed portraits.

What size envelope fits A4 paper?

A4 fits a C4 envelope unfolded. Folded once it fits C5. Folded twice into thirds it fits DL, the standard business envelope outside North America.

What size is Tabloid paper?

US Tabloid (Ledger when oriented landscape) is 11 x 17 inches (279 x 432 mm). Twice the area of US Letter.

What pixel size should I export A4 for print?

At 300 DPI (print standard), A4 = 2480 x 3508 pixels. At 150 DPI, 1240 x 1754. At 72 DPI for screen, 595 x 842. Always export at 300 DPI for professional print.

Mini About Us

We built this because every other paper size chart we found only covered one system. Either ISO or US, never both, and almost never with the print sizes you actually need for posters, photos, and books. This site is a part of the ads4good Network.