Put multiple PDF pages on one sheet (N-up)
N-up imposition places several PDF pages — 2, 4 or more — onto each sheet by embedding the original pages as scaled-down form XObjects arranged in a grid. Text stays vector-sharp because nothing is rasterized. This tool builds the N-up file locally in your browser, with no upload. It is the standard way to save paper on drafts, make lecture-slide handouts, or review many pages side by side.
How it works: pages become form XObjects placed on a grid
PDF has a native mechanism for treating one page as a reusable graphic inside another: the form XObject. A form XObject wraps a complete content stream — with its own fonts, images and coordinate space — into a single named object that any other page can invoke with the Do operator, positioned and scaled by a transformation matrix. This is exactly the mechanism print workflows have always used for imposition, and it is what this tool uses.
For each source page, the tool asks pdf-lib to embed the page as a form XObject in a new document. It then creates output sheets and, for each grid cell, writes a short content-stream instruction of the form q [sx 0 0 sy tx ty] cm /PageN Do Q: save graphics state, apply a matrix that scales the source page down by factor sx = sy and translates it to the cell’s corner, draw the embedded page, restore state. The scale factor is chosen so the source page fits its cell while preserving aspect ratio; a portrait A4 page placed 2-up on a landscape A4 sheet, for instance, scales by about 0.70, which is the familiar A4-to-A5 reduction.
Because the source content streams are embedded verbatim and merely transformed, everything remains vector: text is still real text (selectable in most viewers), lines stay hairline-crisp, and images keep their original data. File size grows only by the small wrapper overhead — the heavy resources are carried over once each — so a 4-up version of a document is typically within a few percent of the original size, not four times smaller or larger. Cells fill in reading order, left to right then top to bottom, and any remainder pages leave the last sheet partly empty.
Worked example: a 48-slide deck as a 4-up handout
A lecture deck of 48 slides, 6.8 MB, in 16:9 landscape. Choosing 4 pages per sheet on portrait A4 produces 12 sheets, each carrying a 2×2 grid of slides scaled to about 48% of their original width. The output file is 6.9 MB — marginally larger than the source, since all 48 slides’ content came along plus twelve new sheet wrappers. Printed double-sided, the whole course session is 6 physical sheets instead of 48, and because slides use 20-point-plus type, the scaled text is still comfortably readable. The same deck at 8-up was generated for archiving, but 24-point text scaled to a quarter width approaches 6-point print — usable for reference, too small for the lecture hall.
Pages per sheet — frequently asked questions
Does putting multiple PDF pages on one sheet blur the text?
No. Each page is embedded as a scaled vector object, not converted to an image, so text and line art stay perfectly sharp at any zoom. Small type can become hard to read simply because it is physically smaller, especially at 8-up.
What does 2-up, 4-up and N-up actually mean?
N-up is printing shorthand for placing N source pages on one sheet: 2-up means two per sheet, 4-up means four in a 2x2 grid. The technique is called imposition and long predates PDF.
How much paper does 4 pages per sheet save?
A 4-up layout cuts the sheet count to a quarter, so a 100-page document prints on 25 sheets single-sided, or 13 sheets duplexed. Combined with double-sided printing that is an eightfold reduction.
Why is there empty space on the last sheet of my N-up PDF?
The grid fills strictly in reading order, so when the source page count is not a multiple of N the final sheet has unused cells. A 10-page file at 4-up yields three sheets: 4, 4 and 2 pages.
Is N-up the same as printing a booklet?
No. Booklet imposition pairs pages out of reading order, for example last with first, so folded sheets read correctly. N-up keeps pages in plain reading order left to right, top to bottom, which suits handouts and code or slide reviews.