Paper size guide
A3 Paper Size
A3 is the large ISO sheet used for posters, charts, proofs, and diagrams when A4 does not provide enough working area.
Quick facts
- Dimensions
- 11.69 × 16.54 in · 297 × 420 mm
- Also called
- A3 size, A3 dimensions, A3 size in inches, 297 x 420 mm paper
- Best for
- classroom posters, large diagrams, A4 two-up proofs, metric graph and planning pages
Overview
A3 paper measures 297 × 420 mm, or about 11.69 × 16.54 inches. It is exactly twice the area of A4, which makes it useful for posters, wall charts, diagrams, and proof sheets that need more room than a standard office page.
A3 is close to US 11×17 Tabloid, but it is not interchangeable. Use the exact page size in your PDF and print at 100 percent scale so metric grids, margins, and labels do not drift.
Printable templates and hubs
Use these printable pages as the closest on-site destinations for this size, related workflow, or layout intent.
Graph Paper 10mm
10mm grid paper for lower grade math and simple charts
A4 Grid 5mm
A4 5mm grid, common for STEM notes
Ledger Paper
Columnar grid for accounting and bookkeeping
Graph & grid paper
Quarter-inch grids, engineering paper, coordinate planes, and specialty math layouts.
other paper
Browse related printable templates and filters for this size cluster.
Supporting articles
A3 Paper Size in Inches: 11.69 x 16.54 in (297 x 420 mm)
A3 paper measures 11.69 x 16.54 inches, or 297 x 420 mm. Compare A3 vs A4 and 11x17, then print posters, charts, and proofs without scaling.
A3 vs A4 Paper: Size, Printing, and Which to Choose
A3 is 297 x 420 mm, exactly twice the area of A4. Compare A3 vs A4, choose the right size, and avoid print scaling mistakes.
Paper Sizes: ISO vs ANSI, Letter, Legal, A4, and 11x17
Compare ISO and North American paper sizes: A4, A3, Letter, Legal, Tabloid, Ledger, and 11x17. Choose the right size before exporting PDFs.
Common questions
- What is A3 paper size in inches?
- A3 paper is about 11.69 × 16.54 inches.
- What is A3 paper size in millimeters?
- A3 paper is 297 × 420 mm.
- Is A3 the same as 11x17?
- No. A3 is 297 × 420 mm, while 11x17 Tabloid is 279.4 × 431.8 mm. They are close enough to confuse, but not interchangeable for scale-sensitive printables.