What size will this print file actually trim to?

Why the page size is the wrong number

Take a business card. The finished card is 90 × 55mm. The file it prints from is 96 × 61mm, because three millimetres of artwork runs off every edge so that the guillotine has something to cut through — that is bleed. Around that sits a margin carrying the trim marks themselves, which on a typical export adds another 33 points, or about 11.6mm, to every side. The page in the PDF can easily be 119 × 84mm for a card that is 90 × 55mm.

So a PDF reader that tells you the page size is telling you the truth and answering a different question. If you order 119 × 84mm you will get something a third bigger than the card you meant, and the cost of finding out is a print run.

The size is usually written in the file

This is the part almost nobody knows. PDF has a dedicated field for the finished size — the trim box — and design software fills it in. InDesign, Illustrator and Acrobat all write one when they export for print, and so does our own bleed and trim marks tool. It exists precisely so the cut size is a fact recorded in the file rather than something a printer has to measure off the marks and hope they got right.

So this tool does not measure anything. It opens the file and reads the box. When the box is there, the answer is exact and this page says declared in the file next to it.

When the file does not say

Plenty of files carry no trim box. A PDF exported for screen, flattened, re-saved out of a viewer, or produced by an office application will usually have none — there was no print intent to record. In that case this tool will not invent one.

What it does instead is show you the page size and what the file would measure if the usual 3mm or 5mm of bleed were trimmed off, and it labels those as arithmetic rather than fact. Often one of them lands exactly on a standard size, and that is your answer. When none of them does, the honest position is that the file does not contain enough to be sure, and guessing is worse than asking.

How to read the result

• Declared in the file — exact. Order that size.
• The file does not say — the readings underneath are worked out from the page size, not taken from the file. Treat a match to a standard size as likely and anything else as a question.
• Bleed each edge — how much is being cut away. Around 3mm is normal here. Zero means the artwork stops dead at the cut line, which is fine for some jobs and risky for anything with a background colour.
• Uneven bleed — the trim is not centred on the sheet. Usually an imposition or artwork placed off-centre, and worth a person looking at it.

What to do once you know

If the finished size matches something on our list, order it — see products and prices. If it is close to a standard size but not exactly on it, that difference is worth a conversation before you commit: a card that is 89 × 54mm can print as a 90 × 55mm card, but the artwork moves relative to the cut and anything close to the edge may not survive it.

And if the file has no trim box and nothing matches, send it to the desk. We will tell you what it is, and what it should be, before anything runs — and you will see a proof either way.

Related

The PDF size checker answers the neighbouring question: how big is the page, and how large can the artwork be printed before it goes soft. Add bleed and trim marks does the opposite of this page — it takes artwork at a finished size and builds the print-ready sheet around it.

Nothing is uploaded

The file never leaves your device. It is opened and read by your own browser, the same as every free tool on this site, which is why this works on a document you would not want to email to a stranger. See our privacy policy for what we do and do not collect.