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What bleed is and why printers need it
Bleed is the extra printed area that extends past the edge of a finished page. When a design runs to the edge of the paper, the printer prints it slightly larger than the final size and then trims the sheet down. The part that gets cut away is the bleed. Without it, even a tiny shift of the cutting blade leaves a thin white hairline along the edge, and that hairline is exactly what ruins an otherwise clean design. Most printers ask for 3 millimetres of bleed on every side, although some large-format jobs use 5 millimetres or more.
This calculator works out the document size a printer needs from your trim size and your bleed value. Enter the finished width and height, add the bleed, and the tool returns the full document size. It also shows the trim size again so you can check both numbers side by side. Use the preset list for common sizes such as A4, A5, US Letter, postcards and business cards, or type a custom size for anything unusual.
How to use the calculator
- Enter the trim size: the finished size of the page after cutting.
- Enter the bleed on each side. The standard value is 3 millimetres.
- Read the document size with bleed and set your design file to exactly that size.
- Keep the trim box at the trim size and export with crop marks, so the printer can see where to cut.
A worked example
Take an A4 flyer, which trims to 210 by 297 millimetres, with 3 millimetres of bleed. The document must be 216 millimetres wide, because 3 millimetres are added on the left and 3 on the right, and 303 millimetres tall, because 3 millimetres are added at the top and 3 at the bottom. If you designed at 210 by 297 and stretched the background to the edge, the printer would have to scale your file or print it short, and either choice risks a white edge. Designing at 216 by 303 from the start avoids the problem completely.
A business card shows why the same rule matters at small sizes. A card trims to 88 by 55 millimetres in many print shops, so with 3 millimetres of bleed the document is 94 by 61 millimetres. The bleed is a much larger share of a small card than of a poster, which is why small items are the ones most often returned for missing bleed. Check the document size before you export, not after the proof comes back.
Common bleed mistakes
- Adding bleed on only two sides. Bleed belongs on every side that the design touches, which usually means all four.
- Extending only the background colour but not the image. Everything that touches the trim edge must extend into the bleed, or the cut will reveal a gap.
- Putting text in the bleed area. Text and logos belong inside the safe area, well away from the trim edge, which is what the safe area margin calculator on this site works out.
- Forgetting bleed on fold-out panels and covers. A cover that wraps around a book needs bleed on the outer edges too, and the spine width calculator helps with the middle of that cover.
Bleed, trim and safe area together
Three boxes describe every print page. The bleed box is the largest: it is the full document size. Inside it sits the trim box, the finished page. Inside the trim box sits the safe area, where text and logos live. If you keep those three boxes in order, most print problems disappear before the file leaves your computer. Set the document to the bleed size, draw the trim box at the trim size, and keep important content inside the safe area. Then export a print-ready PDF with crop marks and bleed included, and check the PDF at full size before sending it. A two-minute check here saves a reprint, and reprints cost far more than the check.