2026-01-15

A4 Paper Size Explained: Dimensions in cm, inches, and pixels

A4 is the default office sheet almost everywhere except North America. The sheet is 210 × 297 mm, which is 21.0 × 29.7 cm, or about 8.27 × 11.69 inches. At 300 DPI that’s roughly 2480 × 3508 pixels.

Why the A series folds so cleanly

ISO 216 keeps a √2 aspect ratio and doubles the area at every step:

• Two A4 sheets side by side make A3
• Fold A4 in half and you get A5
• A0 is defined as one square meter; keep folding and you reach A6

That ratio is why a poster, a handout, and a postcard can share the same layout without rebuilding the margins. A0/A1 for posters, A3 for exams and drawings, A5 for notebooks, A6 for cards.

Letter is not a slightly different A4

US Letter is 8.5 × 11 inches (216 × 279 mm). It’s a bit wider and about 18 mm shorter. Drop an A4 PDF onto Letter stock and the last line often disappears — or you get a fat empty strip. Legal is 8.5 × 14; Tabloid is 11 × 17.

Full mm / inch / pixel tables live on the paper size chart. Once you know which tray your printer actually has, generate lined paper or graph paper at that size instead of scaling later.

Keep print at 1:1

Browsers love “Fit to page.” Switch to Actual size, and match the paper type in the print dialog to the sheet in the tray. PrintPaper.cc draws in millimeters, so 8 mm ruling stays 8 mm if the printer doesn’t shrink the page.

Related tool:Open the paper size chart →