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How wide should my logo watermark be on an A4 page to be visible without getting in the way?

The tool sets the logo's width as a percentage of the page width, from 5% to 100%, and keeps its proportions automatically. For a faint mark in the middle of the page, 25% to 40% works; for a small logo in a corner, 10% to 15%. For example, a 1000 × 400 px logo at 30% on an A4 page comes out about 6.3 cm wide.

Published · 3 min read

Why a percentage and not a fixed size

Because PDFs do not come in one size. An A4 catalog, a Letter-size quotation and a landscape table page can all sit in the same file. A percentage makes the logo take roughly the same share of every page. The height is worked out from the image's own aspect ratio, so the logo is never stretched or squashed.

Real sizes for a 1000 × 400 px logo on A4

A portrait A4 page is 595.28 points, or 21 cm, wide. Here is what the tool calculates:

  • 12%: the logo is 71.43 × 28.57 points, about 2.5 cm wide. Right for a corner beside the page number or your details.
  • 30%: the logo is 178.58 × 71.43 points, about 6.3 cm wide. A clear centred mark that does not blanket whole paragraphs.
  • 40%, the default: the logo is 238.11 × 95.24 points, about 8.4 cm wide. A strong presence that needs low opacity.

Watch out for landscape pages: the percentage is taken from the page width as the reader sees it, so a landscape A4 page is 841.89 points wide and 30% of it gives a logo 252.57 points wide, about two fifths larger than on the portrait page.

Choosing between centre and corner

  1. Decide the purpose: if everyone who sees the page should know where it came from, go central at 25% to 40% with 15% to 25% opacity. If you want a quiet brand signature, go to a corner at 10% to 15% with higher opacity.
  2. In PDF watermark choose Image and upload the logo, ideally a PNG with a transparent background.
  3. Type the percentage in Image width (% of the page width), pick the placement and opacity, and keep the angle at 0 for corners or 45 in the centre if you like the slant.
  4. Press Add watermark and judge the preview at a normal reading distance, not zoomed in.

Does the logo's resolution matter?

Yes, but less than people think. A 1000 pixel logo spread over 6.3 cm gives about 403 pixels per inch, more than enough for screen and print. Even 500 pixels gives about 200 per inch at the same percentage. A 5000 pixel logo adds no visible sharpness, only file size. The image is embedded once however many pages it appears on, but if it is very heavy, shrink its dimensions first with Image resizer.

Common questions

Can I set the size in centimetres directly?

No, the tool works in percentages. Divide the width you want by 21 cm for portrait A4: 6.3 cm, for example, is 30%.

Does the logo get clipped at 100%?

At 100% it is exactly as wide as the page when centred, and with an angle its ends can run off the page. Smaller percentages are safer.