A3
A-Series (ISO 216) · 7 specs
Direct Answer
A3 is an ISO 216 standard paper size measuring 297 × 420 mm (11.7 × 16.5 inches), with a surface area of 0.125 square meters (one eighth of A0). It is the standard large-format paper supported by commercial office multifunction printers (MFPs), widely used for financial spreadsheets, two-page A4 magazine spreads, and engineering diagrams.
Source: ISO 216:2007 (DIN 476-1) · Last reviewed Aug 28, 2026
Specs
| Width × Height (Metric) | 297 × 420 mm |
| Width × Height (Imperial) | 11.7 × 16.5 in |
| Nominal Surface Area | 0.125 m² (125,000 mm²) |
| Exact Aspect Ratio | 1 : √2 (1 : 1.4142) |
| Weight of Standard 80 gsm Sheet | 10.0 grams |
| Halving Relationship | Cut or folded in half yields 2 sheets / 4 pages of A4 |
| Primary Applications | Office spreadsheets, folded A4 booklets, ledger accounting, small posters |
Office Multi-Function Printer Integration
Almost all enterprise office photocopiers and multi-function laser printers feature twin paper cassettes configured for A4 (main drawer) and A3 (secondary drawer). Folding an A3 sheet across its center spine creates an exact 4-page A4 booklet without any trimming.
North American Tabloid Equivalence
A3 (297 × 420 mm) is the international equivalent to the North American Tabloid / Ledger size (11.0 × 17.0 in / 279.4 × 431.8 mm). A3 is slightly wider and slightly shorter than Tabloid/Ledger, but serves the exact same commercial ledger function.