Most paper-ordering mistakes across borders come down to one thing: the size. A4, Letter and Legal sound like variations on the same sheet, but they are three different formats, and a pallet of the wrong one will not suit a printer set up for another. This guide gives the exact dimensions, explains how the sizes differ in real use, and helps you decide which one to order.
A4, Letter and Legal dimensions side by side
| Size | Millimetres | Inches | Typically used for |
|---|---|---|---|
| A4 | 210 × 297 | 8.27 × 11.69 | Standard office size in most of the world (ISO 216) |
| Letter | 215.9 × 279.4 | 8.5 × 11 | Standard office size in the United States, Canada and some Latin American markets |
| Legal | 215.9 × 355.6 | 8.5 × 14 | Contracts, leases, forms and other long-format documents |
| A3 (for reference) | 297 × 420 | 11.69 × 16.54 | Two A4 sheets side by side; see our A3 paper size guide |
A4 vs Letter: close, but not interchangeable
A4 comes from the ISO 216 standard and is used almost everywhere outside North America. Letter is about 6 mm wider and about 18 mm shorter than A4, so it is a squatter sheet. That small difference is enough to cause problems:
- An A4 document printed on Letter is either scaled down or has its bottom margin cut off, depending on the printer settings.
- A Letter document printed on A4 can lose about 3 mm at each side unless it is scaled, and it leaves blank space at the bottom.
- Folders, binders, envelopes and filing cabinets are built around one size or the other, so switching sizes usually means changing those too.
What Legal size is for
Legal paper has the same width as Letter but is 3 inches longer (355.6 mm against 279.4 mm). It became the standard for contracts, leases and court documents in the United States, and it is still used for forms, long tables and spreadsheets that need extra rows. It is not simply a stretched A4: an A4 sheet is 297 mm long, so a Legal sheet is almost 59 mm longer. Some markets also sell an 8.5 × 13 inch “long” or “folio” size, so confirm the exact dimensions before you order.
How to decide which size to order
- Follow your market’s standard. If your customers, forms and filing systems use A4, order A4. If they use Letter, order Letter. Mixing sizes creates scaling problems that staff end up fixing by hand.
- Check what your printers can take. Most office machines handle A4 and Letter from the same tray with an adjustable guide, but some compact printers cannot feed Legal. Look at the maximum paper length in the printer’s specification.
- Look at the documents, not just the paper. Legal is only worth stocking if you regularly print documents that need the extra length.
- List each size separately. Reams and cartons are packed by size and weight, so a mixed order should show each size and quantity on its own line.
Weight and quality are separate from size
Size tells you the shape of the sheet. GSM (grams per square metre) tells you how heavy it is, and brightness and opacity describe how it looks. All three sizes come in different weights, so specify size and GSM together. Our guide to 70, 75 and 80 GSM copy paper explains how to pick a weight.
Ordering A4, Letter and Legal in bulk
We supply A4 copy paper in bulk for wholesale and export, alongside Letter and Legal size grades. Browse the A4 copy paper range, or go straight to the Hammermill copy Letter Size paper, Double A Letter Size Paper and HP Legal Size Paper pages. Tell us the size, GSM, quantity and destination port when you contact our sales team, and ask for the pack specification, because ream and carton configurations can differ by size and grade.
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