pdfpix

Compress a PDF to a target size

or drop one here
Compression level
Target size
Choose a PDF file first.

Name the size you need in kilobytes or megabytes. Four methods work toward it in this browser tab: structural cleanup, image downsampling, font subsetting and a raster fallback. Every candidate is opened again and its text compared with the source. A file that loses more than two percent of its characters is thrown away, not offered.

How to compress a PDF to a target size

  1. Choose the PDF

    Press Choose a PDF, or drop the file on the page. The file is read in this tab and is not sent anywhere.

  2. Name the size

    Choose a compression level, a target below the file's current size, or type your own smaller number in KB.

  3. Press Compress

    Four methods race: copy the pages into a fresh file, re-encode the placed images, cut each embedded font down to the glyphs the pages draw, and, only when no other method reached the target, redraw the pages as images with the text kept on top.

  4. Read the check, then download

    Every candidate is opened again and its characters are counted against the source. The page shows the size, the method that won and the characters kept before it offers the download.

The four methods are described in full, with the measurements behind them, in how it works.

What a target size means here

A target is a byte ceiling, not a quality setting. One kilobyte is 1,024 bytes here, so a 200 KB target means 204,800 bytes and the engine stops below that number rather than at it. Type any number smaller than the file already is, or take one of the preset levels.

Some upload forms count a kilobyte as a flat 1,000 bytes, which makes their limit 2.3% tighter than the same number here. When a file that reads as fitting is refused at the other end, set the target a little lower and run it again.

The common ceilings have their own pages with the number already set: 100 KB, 200 KB, 500 KB and 1 MB are four of them, and each one says how many pages fit at that size.

What the tool does on public files

A public run of 114 documents asks for 16 size targets from 20 KB to 10 MB: text documents, documents with pictures, scans, colour scans and phone photos. Every case produced a verified file. The median file lost 72.5% of its size, the top tenth lost 97.1% or more, and no output was larger than its source.

Per page, a text document comes down to about 14 KB, a document with pictures to about 37 KB, and a scanned page to about 29 KB. A phone photo of a page comes down from about 2.7 MB to about 73 KB at the default setting, and to about 18 KB at the smallest. A page scanned in colour at 300 dpi comes down from about 584 KB to about 99 KB at the default setting, and to about 27 KB at the smallest. The scans are FDA records from the 1990s, kept as 1-bit images at 150 dpi. The colour scans are federal records the National Archives published in 2025. The phone photos are camera JPEGs from a public CC BY dataset, wrapped into PDFs as they are.

Getting a file smaller still

No candidate ships without being read back. The page hands back the smallest file that passed verification, with its size and the method that won, so you can see whether images, fonts or document structure carry the weight.

Three things take a file further, in order. Size breakdown names the images, fonts and streams carrying the weight, which usually points at one or two pages. Delete PDF pages and Split PDF remove or divide what does not have to be sent. If the cap is a guideline rather than a hard limit, a larger target keeps more detail.

How to compress a PDF covers which of the four methods does the work on which kind of document, and Compress a PDF without losing quality covers what can be reduced with no visible change to the page.

Questions

Is my PDF uploaded to a server?
No. The compression runs in this browser tab. No part of the file is sent anywhere, no account is needed and nothing asks you to sign in.
Does the text stay selectable?
Yes. Every candidate file is opened again with pdf.js and its non-space characters are counted against the source. A candidate that keeps less than 98% is refused and a different one ships. In the public test run, every output kept at least 99.99% of its characters.
How small can a PDF get?
A text page comes down to about 14 KB and a scanned page to about 29 KB, so 1 MB holds about 70 text pages, 30 scanned pages or 55 phone photos of pages. Across the public run the median file lost 72.5% of its size, and no output was larger than its source.
What if my file needs to go smaller?
The tool offers one more step, the smallest setting. It redraws the pages at a lower resolution, states what that costs before you press, and lets you put the two files side by side at true size before you decide. A black and white scan page is already a compact 1-bit image at 150 dpi, so the default methods give it its smallest form.
Do scans compress as well as text documents?
Both compress well. A text page comes down to about 14 KB and a scanned page to about 29 KB. A phone photo of a page comes down from about 2.7 MB to about 73 KB at the default setting, and to about 18 KB at the smallest. A page scanned in colour comes down from about 584 KB to about 99 KB at the default setting, and to about 27 KB at the smallest.
Which files does it work on?
Any PDF your browser can open, including scans. A scan carries no text to count, so there the picture comparison is the evidence instead. The title and the author of the source are carried into the output.

Related tools

Each runs in a browser tab like this one, reads its own output back before the download, and needs no account. The footer links every tool.

Where to go next