How to calculate print bleed
- Choose the finished trim format or enter custom millimeter dimensions.
- Use the bleed required by your printer—3 mm is common, but specifications vary.
- Choose a safe margin and output DPI.
- Create your design at the full artwork size, extend backgrounds through the bleed, and keep text inside the safe zone.
Worked A4 example
A4 trim is 210 × 297 mm. With 3 mm bleed on every edge, the document becomes 216 × 303 mm. At 300 DPI that is approximately 2551 × 3579 pixels.
Common print mistakes
Adding 3 mm only once is incorrect: it must be added on both sides, so width and height each grow by 6 mm. Do not place trim marks inside the final artwork, and never assume your printer uses the same bleed as another supplier.
Why is bleed added twice?
Bleed extends beyond both left and right edges and both top and bottom edges.
Is 3 mm always correct?
No. It is common for commercial print, but your print provider’s specification takes priority.
What is the safe zone?
It is an inset area inside the trim where important text and logos are less likely to be cut.
Are pixel dimensions exact?
They are rounded to whole pixels at your selected DPI; a professional layout app can retain physical measurements directly.