Home / Guides /A Paper Sizes Explained: A0 to A5 in mm, cm and Inches

A simple guide to A0–A5 paper sizes, including their dimensions in millimetres, centimetres and inches, plus the print jobs each size is best suited for. From large-format A0 posters to compact A5 flyers, find the right paper size for your project.

The A series reduces by half in area with each step. A0 measures 841 × 1189 mm, and each following size is created by folding the previous size in half along its long edge. That gives you A1 at 594 × 841 mm (59.4 × 84.1 cm), A4 at 210 × 297 mm, and A5 at 148 × 210 mm (14.8 × 21.0 cm).

• A1 measures 594 x 841 mm, which is 59.4 x 84.1 cm, or 23.4 x 33.1 inches.
• A5 measures 148 x 210 mm, which is 14.8 x 21.0 cm — exactly half an A4 sheet.
• A3 is bigger than A4: A3 is 297 x 420 mm against A4 at 210 x 297 mm, so A3 has double the printable area.
• Every A size shares the same 1:1.414 proportion, so a design set up at A4 scales to A0 with no re-cropping.
• A0 at 841 x 1189 mm is the largest A size in ordinary use and the usual choice for site plans and full-height posters.

Yes. A3 measures 297 × 420 mm, while A4 measures 210 × 297 mm, making an A3 sheet exactly twice the area of an A4 sheet. Fold an A3 sheet in half across its long edge and it becomes A4.

The same pattern continues throughout the A series: A2 is two A3 sheets, A1 is two A2 sheets, and A0 is two A1 sheets. Going smaller works the same way  A5 is half an A4, and A6 is half an A5.

A1 measures 59.4 × 84.1 cm, or 594 × 841 mm. In inches, that’s 23.4 × 33.1 in. It’s a popular poster size in Australian retail, offering enough scale for clear visibility across a shop floor while still fitting many standard snap frames.

A5 measures 14.8 × 21.0 cm, or 148 × 210 mm. In inches, it is 5.8 × 8.3 in. An A5 sheet is exactly half the size of A4, allowing two A5 flyers to be produced from a single A4 sheet with one cut down the middle. This makes A5 a cost-effective choice for high-volume flyers, handbills and promotional materials.

The A series is used for printed materials, the C series is designed for envelopes that hold them, and the B series provides sizes in between. A C4 envelope (229 × 324 mm) fits an unfolded A4 sheet, while a C5 envelope (162 × 229 mm) fits an A4 sheet folded once.

B sizes are useful when an A size is slightly too small for the job. B1 measures 707 × 1000 mm, while B2 measures 500 × 707 mm both popular choices for larger event, concert and gig posters.

Supply artwork at the final print size, with 3 mm of bleed on every edge. Keep important text and artwork at least 5 mm inside the trim line to prevent anything being lost during finishing and cutting.

For sizes up to A3, prepare artwork at 300 dpi. From A2 upwards, 150 dpi at final size is generally sufficient, as larger prints are typically viewed from further away while keeping file sizes more manageable.

For best results, supply a print-ready PDF with fonts embedded or outlined, and use CMYK colour rather than RGB for print production.