Paper Size Comparison

Common Sizes Quick Reference
Name mm inches Use
A4210 × 2978.27 × 11.69International standard
Letter215.9 × 279.48.5 × 11US/Canada standard
A3297 × 42011.69 × 16.54Drawings, posters
Tabloid279.4 × 431.811 × 17US large format
A5148 × 2105.83 × 8.27Notebooks, booklets
Legal215.9 × 355.68.5 × 14US legal documents
B5176 × 2506.93 × 9.84Books (international)
DL110 × 2204.33 × 8.66Business envelope

A4 vs Letter: What's the Difference?

A4 (210 × 297mm) is the international ISO standard used in most countries. Letter (215.9 × 279.4mm) is the North American standard.

Letter is 6mm wider but 18mm shorter than A4. The aspect ratio also differs: A4 is 1:1.414 (√2), Letter is 1:1.294.

When printing a US Letter document on A4 paper, the bottom may be slightly cut off. When printing A4 on Letter, there may be small white margins on the sides.