Add crop marks and bleed to a PDF
Crop marks are thin corner lines that tell a print shop's cutter exactly where to trim a printed sheet, and bleed is the extra margin of ink beyond that trim line that prevents white edges. This tool enlarges each PDF page by a bleed-and-slug allowance, centers your original artwork, draws corner trim marks, and writes real /TrimBox and /BleedBox entries (3 mm standard or 5 mm) into the file — all locally in your browser.
How it works
A press-ready PDF page is really three nested rectangles. The media box is the whole sheet the file describes, including waste. Inside it sits the bleed box, the area ink must reach. Inside that sits the trim box, the finished page size after cutting. Consumer PDFs usually collapse all three into one rectangle, which is why print shops bounce them back: the imposition software has nothing to cut to. This tool rebuilds the proper hierarchy from your existing page.
For each page it creates a new, larger page: your original size plus the chosen bleed (3 mm or 5 mm) on every side, plus a further slug strip that gives the marks room to live. Your original page content is embedded and centered on this larger canvas, unscaled, so nothing in the artwork moves or resizes. The tool then draws eight short hairlines — two per corner, offset so they never cross into the bleed area — indicating the horizontal and vertical cut positions. Because the marks sit outside the bleed zone, they end up on waste paper: present for the cutter, absent from the finished piece.
Finally it writes the geometry into the page dictionaries as real PDF entries: /TrimBox is set to your original page rectangle, /BleedBox to that rectangle expanded by the bleed distance, and /MediaBox to the full enlarged sheet. Prepress tools such as imposition software and preflight checkers read these boxes numerically, so the cut size travels with the file instead of being inferred from the drawn marks.
One honest limitation: the tool cannot invent bleed content. If your background color or photo stops exactly at the original page edge, the new bleed zone around it stays white, and a slightly deep cut can still expose a white sliver. Real bleed must be designed in — extend backgrounds 3–5 mm past the trim line in your layout program, export at the enlarged size, and use this tool when you need marks and boxes added to an already-bled file or when your edges are safely white anyway.
Illustrative example: A5 flyer to a press-ready file
Illustrative scenario, not a recorded benchmark. File sizes, timings and results depend on the input and device. Try the reproducible samples.
A two-page A5 flyer (148 × 210 mm, 940 KB) is processed with the 3 mm standard setting. Each output page grows to approximately 166 × 228 mm: 148 + 2 × 3 mm bleed + 2 × 6 mm slug across the width, and the same additions on the height. The trim box reads exactly 148 × 210 mm (419.5 × 595.3 points), the bleed box 154 × 216 mm, and eight corner marks sit in the slug. The output file is 951 KB — barely larger, since the original pages are embedded once, not re-rendered. Opened in a preflight tool, the file now reports a defined trim size instead of "trim box missing," which is precisely the check many online print portals run before accepting an order.
Frequently asked questions
What is the difference between the trim box and the bleed box?
The trim box is the finished page size after the guillotine cut, and the bleed box is the slightly larger area that ink must cover so no white sliver appears if the cut lands a fraction off. This tool writes both boxes into each page so prepress software reads the sizes instead of guessing.
Can this tool create bleed for artwork that stops at the page edge?
No. Bleed content has to exist in the artwork itself; the tool adds space and boxes around your page but cannot invent image data beyond the original edge. If your design has backgrounds that should bleed, extend them 3 to 5 mm past the trim line in your design program first.
Should I choose 3 mm or 5 mm bleed?
3 mm is the common standard for flyers, business cards and most digital printing in Europe; 5 mm is often requested for large-format work, packaging or presses with looser cutting tolerance. Use whatever your print shop's spec sheet asks for — when in doubt, ask them.
Why are the trim marks drawn outside the bleed area?
Marks must survive until the cut but never appear on the finished piece. Placing them beyond the bleed zone means they sit in waste paper that is trimmed away, while ink inside the bleed still covers any cut position within tolerance.
Will my page get bigger after adding crop marks?
Yes, the media box grows by the bleed plus a slug strip on every side — an A4 page with 3 mm bleed becomes about 226 × 313 mm. The finished, trimmed size recorded in the trim box remains exactly your original page size.