Common paper sizes (A4, Letter…)
The international A series, North American Letter/Legal sizes and DL/C5/C4 envelopes: good to know before printing or mailing something.
A series (ISO 216, international)
| Size | Dimensions (mm) | Common use |
|---|---|---|
| A3 | 297 × 420 | Posters, large charts |
| A4 | 210 × 297 | Office standard (letters, résumés, invoices) |
| A5 | 148 × 210 | Notebooks, flyers |
| A6 | 105 × 148 | Postcards |
In the A series, each size is obtained by folding the previous one in half along its length: two A5 sheets side by side make an A4, two A4 make an A3.
North American sizes
| Size | Dimensions | Use |
|---|---|---|
| Letter | 8.5 × 11 in (215.9 × 279.4 mm) | Office standard in the US and Canada |
| Legal | 8.5 × 14 in (215.9 × 355.6 mm) | Legal documents |
| Tabloid | 11 × 17 in (279.4 × 431.8 mm) | Posters, spreads |
Common envelope sizes (Europe)
| Size | Dimensions | Use |
|---|---|---|
| DL | 110 × 220 mm | An A4 letter folded in three |
| C5 | 162 × 229 mm | An A4 letter folded in half |
| C4 | 229 × 324 mm | A flat, unfolded A4 sheet |
A PDF designed for Letter often prints with shifted margins on a printer set to A4 (and vice versa): check the page size before sending a document internationally.
Image resolution for printing
| Use | Recommended resolution |
|---|---|
| Screen only | 72–96 ppi (pixels per inch) |
| Office printing | 300 ppi |
| Large format (poster seen from afar) | 150 ppi is enough |
An image printed at A4 (210 × 297 mm) at 300 ppi needs roughly 2480 × 3508 pixels.
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