A3 is the size people reach for when A4 is too small: drawings, posters, wide spreadsheets and menus. It is also a size where ordering mistakes cost more, because A3 paper is heavier to ship and needs a printer that can actually feed it. Here is what to know before you buy.
A3 paper dimensions
A3 measures 297 × 420 mm (11.69 × 16.54 inches). It belongs to the ISO 216 A-series, where every size is exactly half the area of the one above it. That means an A3 sheet equals two A4 sheets side by side, and folding A3 in half gives you A4.
| Size | Millimetres | Inches | Relationship |
|---|---|---|---|
| A5 | 148 × 210 | 5.83 × 8.27 | Half of A4 |
| A4 | 210 × 297 | 8.27 × 11.69 | Half of A3 |
| A3 | 297 × 420 | 11.69 × 16.54 | Two A4 sheets |
| A2 | 420 × 594 | 16.54 × 23.39 | Two A3 sheets |
Because the proportions stay the same from one size to the next, you can copy A4 up to A3 at about 141%, or A3 down to A4 at about 71%, without cropping or distortion. In North America the closest equivalent is Tabloid (also called Ledger), at 11 × 17 inches. It is near A3 but not identical, so the two are not interchangeable. If you also work with Letter and Legal, see our comparison of A4, Letter and Legal paper sizes.
What A3 paper is used for
- Architectural, engineering and CAD drawings printed on office machines
- Posters, notices, menus and signage
- Wide spreadsheets, charts and schedules that do not fit on A4
- Presentation handouts, calendars and planners
- Print-shop work such as brochures and booklets printed on A3 and folded down to A4
Choosing the right GSM for A3
Larger sheets show flaws more, so weight matters. For everyday drawings and drafts, 70 to 80 GSM is usually enough. For posters and presentations, or double-sided prints where show-through would be visible, 90 to 100 GSM gives a more solid feel and better opacity. Heavier paper costs more per sheet and weighs more per carton, so match the weight to the job rather than ordering the heaviest sheet for everything.
What to check before ordering A3
- Printer support. A standard desktop A4 printer cannot print A3. You need an A3 printer or multifunction copier, and you should check the tray’s maximum paper weight and whether it can print double-sided on A3.
- Handling weight. An A3 sheet at 80 GSM weighs about 10 g, so a 500-sheet ream is roughly 5 kg. If cartons are packed five reams to a carton, that is about 25 kg of paper per carton before packaging, twice a comparable A4 carton. Plan lifting and shipping weights accordingly.
- Storage. Large sheets curl more readily when the air is humid. Keep reams sealed, flat and off the floor until you are ready to use them.
- Consistency. If you print the same job over several months, order the same grade each time so brightness and finish do not change between runs.
Ordering A3 copy paper in bulk
Our A3 copy paper range covers weights from 70 to 100 GSM. Compare Double a Premium A3 Copy Paper, Supreme A3 Copy Paper, Smart Copy Paper A3 and Copy Paper A3, then contact us with your GSM and quantity for bulk pricing and export shipping. For the business case for heavier sheets, read why businesses need premium A3 copy paper.
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