A1
A-Series (ISO 216) · 7 specs
Direct Answer
A1 is an ISO 216 standard paper size measuring 594 × 841 mm (23.4 × 33.1 inches), with an exact surface area of 0.500 square meters (half of A0). It is the premier standard format for architectural blueprints, structural engineering drawings, municipal planning maps, and large-format flipcharts.
Source: ISO 216:2007 (DIN 476-1) · Last reviewed Aug 28, 2026
Specs
| Width × Height (Metric) | 594 × 841 mm |
| Width × Height (Imperial) | 23.4 × 33.1 in |
| Nominal Surface Area | 0.500 m² (500,000 mm²) |
| Exact Aspect Ratio | 1 : √2 (1 : 1.4142) |
| Weight of Standard 80 gsm Sheet | 40.0 grams |
| Halving Relationship | Cut in half yields 2 sheets of A2 |
| Primary Applications | Architectural blueprints, conference presentation boards, large flipcharts, theatrical event posters |
Architectural and CAD Plotting
A1 is the most widely printed sheet size on professional roll-fed inkjet plotters in architectural and engineering studios outside North America. It offers enough resolution for detailed multi-room floor plans, HVAC conduit layouts, and electrical schematics while remaining small enough to lay flat across standard drafting tables.
Direct Weight Derivation
Because A1 is exactly 0.5 m², one sheet of standard 80 gsm bond paper weighs exactly 40.0 grams, and a 500-sheet ream weighs 20.0 kg.