PDF Page Sizes Explained: A4 vs Letter vs Legal, With Exact Dimensions
A4 and US Letter differ by less than two centimetres in each direction, and that tiny gap is enough to truncate tables, shift page breaks and make a submission portal reject an otherwise perfect file. Page size is the most ignored property of a PDF, right up until it costs you something.
The exact dimensions, in every unit
| Size | mm | inches | points (1/72 in) | Where it rules |
|---|---|---|---|---|
| A4 | 210 x 297 | 8.27 x 11.69 | 595 x 842 | India, EU, UK, most of the world |
| US Letter | 216 x 279 | 8.5 x 11 | 612 x 792 | USA, Canada, Philippines |
| US Legal | 216 x 356 | 8.5 x 14 | 612 x 1008 | US contracts, some affidavits |
| A3 | 297 x 420 | 11.69 x 16.54 | 842 x 1191 | Drawings, spreadsheets on paper |
Notice the shape difference, not just the size: A4 is narrower and taller than Letter. A table designed for Letter's extra width will touch the margins on A4, and an A4 document printed on Letter loses roughly two centimetres of height, which is exactly where footers live.
Why US prints go wrong in India, and vice versa
Most mismatches are silent. The PDF says A4, the printer tray holds Letter, and the driver scales or clips without asking. In the other direction, a Letter-sized file sent to an Indian print shop gets squeezed to fit A4, shrinking text by about three percent, which is invisible on screen and obvious on paper next to the original.
Portals are stricter than printers. Several submission systems validate the page box in points and reject anything that is not exactly 595 x 842 for A4, because their downstream stamping assumes it. "Close enough" is not a state a validator understands.
How to check a PDF's page size in ten seconds
- Open the file in PdfPixel's PDF Stats Analyzer, which reports each page's box in points and millimetres without uploading anything.
- Compare against the table above. Mixed sizes inside one file (one Letter page hiding among A4) are the nastiest case, and per-page reporting is the only way to catch them.
- If the size is wrong, decide whether you need a resize or a crop: resizing rescales content, cropping changes the canvas. Scans usually want a crop; born-digital documents usually want a proper re-export at the right size.
Fixing a mismatched file without re-doing the work
When the content is fine and only the canvas is wrong, a crop to the target box with a small margin recovers most files: keep the content, replace the page box, and the validator is happy. Use Crop PDF when the artwork sits inside safe margins, and re-export from the source application when text genuinely needs reflow, because scaling text down to squeeze Letter into A4 hurts readability more than a re-export costs in time.
The page box is a promise to every printer and portal downstream. Keep it exact.
Which size should you standardise on?
For anything submitted in India: A4, 595 x 842 points, portrait, margins of at least 15 mm. For US correspondence: Letter. For contracts that cite "legal size": Legal, and check whether the citation means US Legal or a local variant, because the two are not the same sheet. When a form is silent, A4 is the safer default globally, and Letter the safer default for US-only pipelines.
Frequently asked questions
Does page size affect file weight?
Barely. The box is metadata; weight comes from images and fonts. A 40-page A4 scan and the same scan as Letter weigh essentially the same.
Can one PDF mix A4 and Letter pages?
Technically yes, and it is a classic source of print disasters. Validators that check size usually check every page, so one stray Letter page fails the whole file.
Is 210 x 297 mm exactly 595 x 842 points?
To the rounding the format uses, yes: 595.28 x 841.89 points, reported as 595 x 842. Tools that truncate rather than round can show 594, which some strict validators flag.
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