Bleed, Trim and Safe Area: Why Printers Keep Asking for 3mm
Why printers ask for 3 mm of bleed, what it does, and how to set it up without any design experience.
From the team at The Printing Shop.
If a colour or a picture runs to the edge of your print, your file needs bleed. Once you understand why it exists, it is easy to set up.
The three lines
- Trim line: where the paper will be cut. This is your finished size.
- Bleed: extra image that extends past the trim line, usually by 3 mm on each side. It gets cut away.
- Safe area: a margin inside the trim line, usually at least 3 to 5 mm. Keep important text and logos inside it.
Why it is needed
Print is cut in stacks, and no cutting machine is perfect. If a sheet moves by even a millimetre, an image that stops exactly at the trim line can leave a thin white sliver along the edge. By extending the image past the cut, a small movement does not show. For the same reason, text that sits too close to the edge can look uneven or risk being clipped.
Working out your file size
Add 3 mm to each side. So:
| Finished size | File size with bleed |
|---|---|
| Business card, 85 x 55 mm | 91 x 61 mm |
| A6, 105 x 148 mm | 111 x 154 mm |
| A5, 148 x 210 mm | 154 x 216 mm |
| A4, 210 x 297 mm | 216 x 303 mm |
How to set it up
Adobe InDesign or Illustrator: set bleed to 3 mm when you create the document, then tick "Use document bleed settings" when exporting to PDF.
Canva: turn on "Show print bleed" in the file menu, drag backgrounds to the edge of the page, then download as "PDF Print" with crop marks and bleed.
Microsoft Word or PowerPoint: there is no true bleed setting. You can make the page 6 mm larger in each direction and allow images to run off the edge, or simply send us your file and we can sort it out for you.
Do I always need bleed?
No. A document with plain white margins, such as a letter or a report, does not need any. Bleed only matters where the ink reaches the edge of the page. If you have a coloured border, think twice: a thin border close to the edge shows any small cutting shift very clearly, so a thicker border or no border is safer.
What about large-format print?
Posters and banners often use different allowances, particularly when they are hemmed or fitted into a frame. A PVC banner with hems needs extra space around key text, and a roller banner has part of its base hidden. Ask us, and we can tell you what the job needs.
If this all sounds like too much
You do not need to do any of it yourself. Our artwork set-up is free when we print the job. Send what you have, and we will check it and add bleed where we can. If your image cannot be extended, we may suggest a small adjustment to the size, and we will show you a proof before we print. See also our checklist for preparing files.