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What pixel width should I choose for a collage I want to print on an A4 page?

Type 2480 in “Output width (px)”. An A4 sheet is 210 mm wide, which is about 2480 px at 300 pixels per inch, a common density for sharp prints. Then check the height the tool calculates: it should stay within about 3508 px, the 297 mm length of the sheet at the same density. If it is taller, choose a wider cell shape or fewer rows.

Published · 3 min read

From millimeters to pixels

An inch is 25.4 mm. The 210 mm width is about 8.27 inches, and times 300 that gives 2480. The 297 mm length is about 11.69 inches, or 3508 px. That is a full portrait A4 page at 300. For everyday prints, such as a sheet pinned up in the shop, 150 is usually enough, which makes the page 1240 wide and 1754 tall and the file much lighter.

The height is what needs your attention

The Image collage maker maker does not let you type a height; it follows from the width, the number of rows, the cell shape and the spacing. So you can enter 2480 correctly and still end up with an image longer than the sheet.

Worked example

6 photos in 2 columns, a 2480 width, a 20 gap, a 60 margin and a 1:1 cell shape: the output is 2480 × 3670, longer than 3508.

The same settings with a 4:3 cell give 2480 × 2794 and fit the page with some space left below. A 3:2 cell gives 2480 × 2500.

If you want to fill more of the sheet, some combinations come closer to the full length: 4 photos in 2 columns with a portrait 3:4 cell give 2480 × 3260, and 12 photos in 3 columns with a 1:1 cell give 2480 × 3276, both with a 20 gap and a 60 margin.

What if the collage is longer than the page?

Nothing is lost, but with “fit to page” the printer shrinks it until its length fits, so it gets narrower and white strips appear down both sides. Without fitting, the bottom may be cut off. It is easier to fix before downloading: change the cell shape or the column count and watch the number until it reads 3508 or less.

Printing: image or PDF?

  1. Download the collage as JPEG or PNG. The image carries no fixed paper size, so the printing software decides how big it comes out.
  2. If you will print from a phone or send the file to a print shop, turn it into an A4 PDF with Images to PDF: choose A4, the margin you want in millimeters and “Fit inside”. The file then arrives with a defined page size that does not depend on someone else's settings.
  3. If you send the image straight to a print shop, tell them it was made for portrait A4 at 300.

Tips for a clean print

  • A 60 px margin is about 5 mm at 300, keeping the photos away from the edge that some home printers cannot reach.
  • Original phone photos are normally plenty for a cell 1170 px wide. Small images saved from chats will look softer on paper.
  • The gap and margin use the background color, and white saves ink.

Common questions

Can I print the collage on landscape A4?

Yes. The width is then 3508 and the height should stay within about 2480. Use fewer rows or wider cell shapes.

Is 2480 × 3508 within the tool's limit?

Yes, it is about 8.7 megapixels, and the output cap is 40 megapixels.

What about A5?

Same arithmetic: A5 is 148 mm wide, about 1748 px at 300.