Resize PDF Pages (Change Page Size)

About the Resize PDF Pages (Change Page Size)

Change the paper size of a PDF: A4, US Letter, US Legal, A3, A5, A6, B5, Tabloid or any custom size. Scale to fit shrinks or enlarges each page so it fills the new size without distortion; Shrink only scales down pages that are too big and leaves smaller ones at 100%; Keep 100% never scales and simply adds white space (or trims the edges when the new page is smaller). PDFs with a mix of page sizes come out with one size, and Auto orientation keeps landscape pages landscape.

For printing you can add margins, a binding margin (gutter) that switches sides on double-sided pages, and a bleed with the trim size recorded in the file, as print shops expect. The page content is not redrawn or turned into images: each page keeps its own text and vector graphics, placed on the new page with one scale-and-move instruction, and links, bookmarks, comments and form fields move with it. Everything happens in your browser — the file is never uploaded.

Common uses

• Printing US Letter files on A4 paper (or A4 on Letter) without cutting off the edges.
• Combining scans and documents of different sizes into one evenly sized PDF.
• Adding a binding margin before printing a thesis, report or manual double-sided.
• Preparing a file for a print shop that asks for 3 mm or 0.125 in bleed and a trim box.
• Making a court, visa or exam portal upload meet a required page size such as A4.

Paper sizes

• A3 297 × 420 mm · A4 210 × 297 mm · A5 148 × 210 mm · A6 105 × 148 mm · B5 176 × 250 mm — ISO 216. Each A size is half the one before it, and A0 has an area of one square metre.
• US Letter 8.5 × 11 in (215.9 × 279.4 mm) — size A in ANSI/ASME Y14.1.
• Tabloid 11 × 17 in (279.4 × 431.8 mm) — size B in ANSI/ASME Y14.1.
• US Legal 8.5 × 14 in (215.9 × 355.6 mm) — the customary North American legal size.

PDF measures pages in points: 1 point = 1/72 inch and 1 inch = 25.4 mm, so A4 is 595.28 × 841.89 points and Letter is 612 × 792. Custom sizes can be 1.1 mm to 5.08 m on each side, the range PDF readers support.

How the scale is worked out

The content area is the new page minus the margins. With Scale to fit, scale = the smaller of (content-area width ÷ page width) and (content-area height ÷ page height), so the whole page fits and nothing is stretched; the page is then centred in the content area. Shrink only uses the same scale but never more than 100%. Keep 100% uses a scale of exactly 1, so measurements on the page stay true — handy for drawings and forms that must print at actual size.

For example, an A4 page on Letter: 612 ÷ 595.28 = 1.028 across, 792 ÷ 841.89 = 0.941 down, so the scale is 94.1%.

Binding margin and bleed

A binding margin (gutter) is extra space on the edge that will be stapled, punched or bound. For double-sided printing, page 1 is a right-hand page with the binding on its left, page 2 has it on the right, and so on. Top binding (notepads, calendars) works the same way between the top and bottom edges.

A bleed is extra paper around the finished (trim) size so colour that runs to the edge has no white slivers after cutting. The tool makes the page larger by the bleed on every side and records the finished size as the TrimBox and the full sheet as the BleedBox (ISO 32000-1 §14.11.2), which is what print shops check. The bleed stays blank unless you choose Extend edges into the bleed: the outer strip of the page is then mirrored outwards — only along edges the content actually reaches, so nothing is copied onto the page itself.

What stays the same

The pages are not converted to images or redrawn: text stays selectable and searchable, fonts stay embedded, and vector graphics stay sharp at any zoom. Links, bookmarks and other jump targets are moved to the same spot on the resized page; comments, highlights and form fields move and scale with the content; accessibility tags are untouched. Pages you leave out of the page selection, and pages that already have the new size, are not changed at all.

Sources

• ISO 216 — A and B series paper sizes.
• ANSI/ASME Y14.1 — sheet sizes A (8.5 × 11 in) and B (11 × 17 in).
• ISO 32000-1:2008 §8.3.2.3 (one default unit is 1/72 inch), §14.11.2 (MediaBox, CropBox, BleedBox, TrimBox) and Annex C (page sizes from 3 to 14,400 units).

Limitations

• Encrypted or password-protected PDFs must be unlocked first with Unlock PDF.
• Saving rewrites the file, so existing digital signatures will show as invalid. Resize first, then sign.
• With Keep 100%, anything outside the new page is cut off — the preview shows what remains.
• Content is always centred between the margins; there is no option to align it to a corner.
• Form fields keep their font size, so text typed into a field on a much smaller page may no longer fit the box.
• Mirrored bleed copies the outer few millimetres of the page; it is not a substitute for artwork that was designed with a bleed.
• The first use downloads the PDF engine once, so it needs an internet connection.

Privacy

Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.