The LaserWriter 12/640 PS printer supports the following page sizes and imageable areas:
| Paper Type | Physical Page Size (points) | Imageable Area (points) |
| Letter | 612 x 792 | 587.52 x 767.88 |
| Lettersmall | 612 x 792 | 562 x 742 |
| Legal | 612 x 1008 | 587.52 x 983.88 |
| Legalsmall | 612 x 1008 | 562 x 958 |
| A4 | 595 x 842 | 572.16 x 817.8 |
| A4small | 595 x 842 | 545 x 792 |
| A5 | 420 x 595 | 399.36 x 570.84 |
| B5 (JIS) | 516 x 729 | 491.52 x 704.88 |
| Executive | 522 x 756 | 499.2 x 732.48 |
| EuroPostCard | 284 x 420 | 272.64 x 391.50 |
| Envelope Type | Physical Size (points) | Imageable Area (points) |
| COM-10 | 297 x 684 | 272.64 x 656 |
| Monarch | 279 x 540 | 257.28 x 512 |
| C5 | 459 x 649 | 433.92 x 621 |
| DL | 312 x 624 | 288 x 596 |
Notes:- The fractions are due to conversion from pixels to points.
- To convert from points to inches divide the number by 72 (1 inch = 72 points).
LaserWriter Printable Area Margins- Left = 4.0 mm (0.157 in or 11.34 points)
- Right = 4.0 mm (0.157 in or 11.34 points)
- Top = 4.0 mm (0.157 in or 11.34 points)
- Bottom = 4.0 mm (0.157 in or 11.34 points)
- For heavy paper (Postcard and Envelopes) the top margin is 6.00 mm.
- Maximum printable line: 208 mm (8.19 in) standard mode
- The default paper size is lettersmall.