Resizing a PDF changes the physical page dimensions of every page — measured in PDF points where 72 points equal one inch — and scales the drawn content to match. The standard page sizes the tool targets are A4 at 595 by 842 points (8.26 by 11.69 inches), US Letter at 612 by 792 points (8.5 by 11 inches), and US Legal at 612 by 1008 points (8.5 by 14 inches), and you can also scale by any percentage you type in. If your goal is to shrink a PDF so it weighs roughly 100 KB on disk, this is the honest moment to clarify what page resizing does and what it does not: the tool rewrites the geometry of each page and rescales the artwork sitting on it, but it does not re-sample images, strip fonts, or discard PDF objects, so the downloaded file is often a similar size to the original and can in some cases be larger. Resizing is the right job when you need consistent paper dimensions for printing, binding, or submission requirements. Reaching a 100 KB target is a separate job that needs an image-aware compressor. The rest of this article walks through exactly how Resize PDF works, how to pick between Standard and Percentage modes, and when to switch to a compression tool instead.
What Resize PDF Changes on Each Page
A PDF page is a rectangle drawn in points. The Resize PDF tool rewrites that rectangle on every page and rescales the content drawn inside it, so text, images, and shapes keep their position on the new geometry rather than being clipped or pushed off the edge. In Standard size mode the tool reads each page's current dimensions one by one, then sets every page to a single target — A4, US Letter, or US Legal — chosen in either portrait or landscape orientation. In Percentage mode the tool applies one factor to every page, so a value of 50 percent halves each page and 200 percent doubles it, with the contents scaling along with the geometry.
This distinction matters because the phrase "resize a PDF" means two very different things to different people. To a print shop it means "match the paper size my printer expects." To a job portal it means "fit the dimensions on the form." To someone trying to email a file under an attachment cap, it usually means "make the file weigh less." The geometry-changing job is what this tool does; the weight-changing job is what an image-aware compressor does. Confusing the two is the most common reason people are disappointed after running a resize and finding the file is roughly the same number of megabytes as before.
How to Resize a PDF Online in Three Steps
- Click Browse PDF and pick the file you want to resize, or drag it onto the page. The file is read locally in your browser, so it never touches a server.
- Pick a target. In Standard size choose A4, US Letter, or US Legal with a portrait or landscape orientation and a scaling mode of Fit or Stretch; in Percentage enter any value such as 50, 75, or 200.
- Click Resize PDF, then download the resized copy from the result link. The original file is left untouched and every page in the output is rescaled the same way.
If your PDF is password-protected or corrupted, the tool reports it clearly so you can unlock or repair the file first; it does not silently produce a half-broken result. Each page is processed individually in Standard mode, so a document with mixed original sizes — for example a slide deck exported at 1280 by 720 points and a scan captured at an odd width — comes out uniform in the end.
Standard Size, Percentage, Fit, and Stretch Compared
| Mode | What you set | How content is scaled | Best for |
|---|---|---|---|
| Standard — Fit | A4, Letter, or Legal; orientation | Single scale factor, centered with even margins | Faithful reproduction; nothing distorted or cropped |
| Standard — Stretch | A4, Letter, or Legal; orientation | Width and height scaled independently | Filling a frame edge to edge when proportions can change |
| Percentage | Any value (e.g. 50, 75, 200) | Single scale factor relative to current size | Halving, doubling, or any custom relative change |
Fit is the safer default for most jobs. The tool computes one factor — the smaller of target-width divided by current-width and target-height divided by current-height — applies it to the whole page so the artwork never stretches out of shape, and centers the result with equal margins on whichever axis has spare room. Stretch is the option to reach for when you want the artwork to fill the target rectangle edge to edge regardless of how the aspect ratio changes. Percentage is the most flexible mode: a value of 50 reduces every page to half its current size in both dimensions, and a value of 200 enlarges it to double.
The three standard paper sizes, expressed in PDF points and inches, are the following:
| Paper size | Points (width × height) | Inches (width × height) |
|---|---|---|
| A4 | 595 × 842 | 8.26 × 11.69 |
| US Letter | 612 × 792 | 8.50 × 11.00 |
| US Legal | 612 × 1008 | 8.50 × 14.00 |
For one quick check on the conversion: 595 PDF points divided by 72 points per inch gives 8.2639 inches, which rounds to the 8.26-inch A4 width above. The same rule applies to every other dimension in the table, and it is the constant the tool uses internally whenever it translates between points and inches.
When Resize Helps You Reach 100 KB (and When It Doesn't)
There is one situation in which changing the page geometry can incidentally make the file a little smaller: when a PDF carries very large pages filled with vector content drawn at a high scale, scaling those pages down to a smaller geometry does reduce the coordinate range the PDF has to describe, and the output can be a few percent smaller as a result. That effect is real but small, and it does not apply to most everyday PDFs. For a 50-page scanned document with embedded JPG photos, switching the page from US Legal to US Letter will not meaningfully change the file size, because almost all of the bytes are sitting inside the embedded images, not in the page geometry.
If your real target is 100 KB on disk, the job that gets you there is image-aware compression — re-sampling photos to a lower resolution, recompressing them at a lower JPG quality, and removing redundant PDF objects. That is the work that Compress PDF and Compress PDF to Size do, and they are the right tool when the goal is byte size rather than paper size. Resize PDF is the right tool when the goal is a specific paper dimension for a printer, a portal, or a binding format.
A useful workflow is to do both in sequence. Resize a slide deck exported at 1280 by 720 points down to US Letter so it prints cleanly, then run the result through a compressor if you also need to drop it under an attachment limit. The two tools solve different problems and compose well: one fixes the geometry, the other fixes the byte count.
Privacy and File Handling
Resize PDF runs entirely in your browser using JavaScript, so the bytes of your PDF are read into memory, processed locally, and written back as a new file that you download directly. Nothing is uploaded to a server, nothing is stored in the cloud, and the contents of your document are not transmitted or logged. The original file is left on your machine exactly as it was, and the resized copy is offered as a download link you can save wherever you like. This makes the tool safe for confidential contracts, medical records, financial statements, and anything else sensitive, because the document stays on your device from the moment you select it to the moment you save the result.
Because the tool works once the page has loaded, it also runs offline if you have the page cached. Password-protected files cannot be read without their password and are reported clearly so you can unlock them first before resizing; pages that carry a rotation flag (common with phone or scanner PDFs) are kept unrotated, so a portrait target can still display sideways until the rotation is reset on the original.
Putting It Together for a 100 KB Target
Start by being clear about which problem you are solving. If you need a PDF whose pages measure A4, US Letter, or US Legal — or any custom percentage scale — open Resize PDF, pick the file, choose the target, and download the result. If you need the file itself to weigh around 100 KB on disk, hand the same file to a compressor instead, or do both in sequence when you need consistent paper dimensions and a lighter attachment at the same time. The two tasks are different, the two tools are different, and naming them honestly is the fastest way to get the outcome you actually want.