A3 paper

A3 paper measures 11.69 inches (297 mm) wide and 16.54 inches (420 mm) tall. It is twice the size of A4, the most common paper format worldwide, and is typically used for posters, architectural drawings, spreadsheets with many columns, and presentation boards. This page covers the exact dimensions, how it fits into the ISO paper system, and common uses.

Dimensions

Area and aspect ratio

A3 has an area of 0.125 square meters, exactly one-eighth of a square meter and twice the area of A4. Like every size in the A-series, it uses the 1:√2 aspect ratio (about 1:1.414), so two A3 sheets side by side match the size of one A2 sheet, and one A3 sheet folded in half produces two A4 sheets.

The ISO 216 A-series system

Each size doubles or halves the one next to it in area. This is why office printers that support A3 can print a document as two A4 pages side by side at full scale, useful for spreadsheets, calendars, and diagrams that need more horizontal space than A4 allows.

A3 vs US Tabloid (Ledger)

US Tabloid, also called Ledger, is the closest American equivalent to A3, but the dimensions do not match exactly. Tabloid is narrower and taller than A3. A document formatted for A3 will not fill a Tabloid page correctly without scaling, and vice versa.

Common uses

A3 is common for architectural and engineering drawings, large spreadsheets, event posters, presentation boards, comic book and manga printing, and children’s art projects in schools. Many office and home printers marketed as “A3 capable” can handle both A4 and A3, giving users flexibility for oversized documents without needing a dedicated wide-format printer.

Practical tips for working with A3

Not every home printer supports A3, so check your printer’s maximum paper size before designing a document at this scale. If you need to print an A3 poster but only have an A4 printer, you can split the design into two A4 pages using “poster print” or “tile” settings found in most printer driver software, then tape the sheets together. For professional printing, most copy shops and print-on-demand services support A3 as a standard option.

Frequently asked questions

What is A3 paper size in inches?

11.69 x 16.54 inches. In millimeters, it is 297 x 420 mm.

Is A3 double the size of A4?

Yes, in area. Two A4 sheets have the same total area as one A3 sheet, and folding an A3 sheet in half produces two A4-sized sheets.

Is A3 the same as US Tabloid?

No. A3 is 297 x 420 mm and US Tabloid is 279 x 432 mm. Tabloid is slightly narrower and taller than A3.

Can a normal printer print A3?

Most standard home and office printers only support up to A4 or US Letter. Printing A3 requires a wide-format printer or splitting the design across multiple A4 pages.

What is A3 paper commonly used for?

Posters, architectural plans, large presentation charts, and school art projects. It gives more room than A4 without the bulk of even larger formats like A2 or A1.

Related objects

• A4 paper
• A5 paper
• US Letter paper
• US Legal paper