Document paper standards

A4 vs Letter: ISO and US paper sizes in pixels

A4 and US Letter are different document standards, not interchangeable names for the same page. Compare their exact dimensions, regional uses and 300 PPI pixel requirements before setting up a document.

5 minute readUpdated 31 July 2026

ISO A-series sizes

A-series sheets keep the same proportions when folded or enlarged between adjacent sizes. Pixel values are rounded because millimetres are converted through the exact relationship of 25.4 millimetres per inch.

SizeMillimetresInchesPixels at 300 PPI
A6105 × 148 mm4.13 × 5.83 in1240 × 1748 px
A5148 × 210 mm5.83 × 8.27 in1748 × 2480 px
A4210 × 297 mm8.27 × 11.69 in2480 × 3508 px
A3297 × 420 mm11.69 × 16.54 in3508 × 4961 px
A2420 × 594 mm16.54 × 23.39 in4961 × 7016 px
A1594 × 841 mm23.39 × 33.11 in7016 × 9933 px

North American document sizes

US Letter is shorter and wider than A4, so substituting one for the other can change line breaks, margins and crop. Choose the page standard expected by the recipient or printer.

SizeInchesMillimetresPixels at 300 PPI
Letter8.5 × 11 in215.9 × 279.4 mm2550 × 3300 px
Legal8.5 × 14 in215.9 × 355.6 mm2550 × 4200 px
Tabloid11 × 17 in279.4 × 431.8 mm3300 × 5100 px

A4 versus Letter at a glance

A4 is taller and narrower, while Letter is slightly wider and shorter. At 300 PPI, Letter needs 70 more pixels across but A4 needs 208 more pixels vertically. Scaling one layout to the other can change line breaks, margins and page count.

Choose the standard required by the printer, recipient, school or organisation. If both versions are needed, create separate layouts or carefully reflow the content instead of stretching the finished page.

CharacteristicA4US Letter
Physical size210 × 297 mm215.9 × 279.4 mm
Inches8.27 × 11.69 in8.5 × 11 in
Pixels at 300 PPI2480 × 3508 px2550 × 3300 px
Portrait ratio1:1.4141:1.294
Common useInternational documentsUS and Canadian documents

Set up the full document, not only the trim

The values above are the finished cut size. If artwork touches an edge, extend it into bleed. Keep text and logos inside a separate safe margin. Bleed and safe-area requirements vary, so use the production template when one is supplied.

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