Add Margin to PDF Pages Online, Free

How to add margins to PDF pages

1. Click Browse Files or drop a PDF onto the box. Files up to 50 MB are accepted.
2. Type a margin in millimetres for each side, or drag the sliders. Built-in presets give 10, 25 or 50 mm on every side.
3. Choose Enlarge page to add space outside the content, or Keep page size to shrink the content and keep A4 as A4. The preview and the size line show the result.
4. To change only some pages, untick All Pages and type a range such as 1-5, 8.
5. Click Download PDF. The file is saved as yourfile_with_margins.pdf.

How the margin is calculated

PDF pages are measured in points, not millimetres. One inch is 72 points and also 25.4 mm, so the tool converts each value with points = mm × 72 ÷ 25.4, which is about 2.835 points per mm.

Enlarge page (default)

The page box is made bigger by the margins and the content stays at 100% size. New width = page width + left + right, and new height = page height + top + bottom.

Example: you want room on the left to punch and file your UPSC Mains answer-writing practice sheets. An A4 page is 210 × 297 mm (595 × 842 points). With a 25 mm left margin and 0 mm elsewhere, the page becomes 235 × 297 mm: the left margin adds 25 × 2.835 ≈ 71 points.

Keep page size

The paper size stays the same and the content is scaled down evenly so it fits inside the margins, then centred in the space left. Scale = the smaller of (width − left − right) ÷ width and (height − top − bottom) ÷ height. For the same A4 page with 25 mm on the left only, the scale is (210 − 25) ÷ 210 ≈ 88%, so text prints about 12% smaller but the file is still A4.

Rotated (landscape) pages are handled the way you see them: the top margin is always added at the top of the page as it appears on screen. Links in the PDF move with the content when it is shrunk.

Tips and common mistakes

• Check the size line under the presets before you download. It shows the first page's size in mm before and after.
• Printing an enlarged page on A4 makes the printer shrink it to fit the paper. If you will print on A4, use Keep page size instead.
• Do not alter official documents such as an admit card or a certificate before uploading them to UPSC, SSC or another exam portal unless the instructions ask for it. Check the official notification for the required format.
• Password-protected PDFs cannot be edited. Save an unprotected copy first.
• Save a preset if you use the same margins often. Presets are kept only in this browser.

Frequently Asked Questions

How do I add margins to a PDF?

Upload the PDF, type the margin you want in millimetres for each side, and click Download PDF. The new file is saved with _with_margins added to its name, and your original is not changed.

Will adding margins change my PDF page size?

Only if you choose Enlarge page. That mode adds white space outside the content, so an A4 page with 20 mm left and right margins becomes 250 mm wide. Choose Keep page size if the file must stay A4; the content is then shrunk to fit inside the margins.

How many points are in 1 mm?

1 mm is about 2.835 points. PDF sizes are measured in points, where 72 points make one inch (25.4 mm), so this tool converts every mm value with points = mm × 72 ÷ 25.4.

Can I add margins to only some pages?

Yes. Untick All Pages and enter a page range such as 1-5, 8. Only those pages get the new margins; the other pages are kept exactly as they were.

Why does my PDF show an error when I upload it?

The most common reason is that the PDF is password-protected or encrypted. Open it with its password, save or print an unprotected copy, and upload that copy. A damaged file or a file that is not really a PDF also cannot be read.

Is my PDF uploaded to a server?

No. The margins are added in your browser with the pdf-lib library, so the file never leaves your device. That makes the tool safe for admit cards, marksheets and other private documents.