PDF Compressor
Compress a PDF to a size you choose. Set a target in kilobytes and the tool works down to it.
Before you use this: This tool rasterises your PDF — text becomes part of an image and stops being selectable or searchable. That is the trade-off required to hit a hard size target. If you need live text, re-export the source at lower image quality instead.
Rendering pages and searching for the best quality that fits…
- Original
- —
- Compressed
- —
- Reduction
- —
- Pages
- —
How to use this tool
- Choose your PDF or drag it onto the box above.
- The target is already set to 500.0 KB. If your file is already under that, it is returned untouched rather than needlessly rasterised.
- Each page is rendered and re-encoded, then the quality is searched until the whole document fits. Our reference (3 pages) finished at 486.7 KB.
- Download the result. Remember the trade-off stated above: hitting an exact size means the text is no longer selectable.
If you need a specific published figure — 100 KB for a scholarship portal, 2 MB for an applicant tracking system — the preset pages go straight there without the setup.
PDF Compressor — the specification
| Target size | Whatever you enter, in KB |
|---|---|
| Method | Pages rendered and re-encoded as JPEG |
| Text | Becomes part of the image — no longer selectable |
| Page limit | 60 pages |
| Maximum input | 100 MB |
PDF Compressor: why uploads get rejected
Landing under 500 KB is necessary but not sufficient. These are the reasons a file that meets the size still gets sent back:
- The PDF is password-protected. Remove the password first — we cannot bypass encryption.
- The document is already well optimised, so rasterising makes it larger. The tool tells you when this happens.
- The target is very small for a text-heavy document, so the text becomes unreadable. Check the output.
- The document exceeds 60 pages, which would exhaust your browser tab’s memory.
How it works
Each page is rendered with pdf.js and re-encoded as a JPEG, then the pages are reassembled into a new PDF with pdf-lib. A binary search over image quality — and, if needed, render resolution — lands the result under your target.
The trade-off, stated plainly: this rasterises the document. Text becomes part of an image, so it is no longer selectable, searchable, or readable by automated systems. That is how most "compress to X KB" services work, and it is the only way to hit a hard size target in a browser — but it is a real cost. If you need the text to stay live, use a smaller scan resolution instead of compressing afterwards.
A measured run of this exact preset
Not an estimate. This page’s own code, run against two documented reference PDFs.
| Input | Result | Change | Outcome |
|---|---|---|---|
| a 3-page scanned document 2.92 MB | 486.7 KB | 84% smaller | Under the 500 KB limit |
| a 4-page text document 10.8 KB | 10.8 KB | unchanged | Already under 500 KB — nothing to do |
What the numbers show
The scanned document went from 2.92 MB to 486.7 KB across 3 pages. Almost all of that saving came from re-encoding the page images, because on a scan the images are the document.
The text document is the instructive one. It started at 10.8 KB — already far under the 500.0 KB target — because text is stored as characters and positions, which costs almost nothing. If your PDF is mostly text and still enormous, the size is coming from embedded images or un-subset fonts, not from the words.
And the trade-off that does not show in a table: reaching a hard size target means rasterising the pages, so the text stops being selectable. That is true of every browser-based tool that hits an exact number, and this page says so rather than leaving you to discover it after you have filed the document.
Who needs PDF Compressor
Any upload portal, email attachment or application system enforcing a hard file size limit.
PDF Compressor — frequently asked questions
What target should I use?
Match whatever limit you have been given, then aim slightly below it — some systems measure the encoded upload, which is larger than the file on disk.
Will my text stay selectable?
No. Reaching a hard size target requires rasterising the pages. If you need live text, re-export the source document at lower image quality instead.
What if my PDF will not go under 500 KB?
The tool reports what it achieved rather than pretending. A PDF that is mostly text is already near its floor and will barely move; a large one is usually carrying embedded images, and those are what compression works on. If it cannot reach the target, the panel tells you the size it reached so you can decide what to do next.
Does compression change the page count or layout?
No. Pages, order and dimensions are preserved. Only the encoding of what is on them changes.
Is this tool really free?
Yes. No account, no trial period, no watermark on the output and no cap on how many times you use it. The site is funded by advertising.
Do I need to install anything?
No. There is nothing to download and no extension to add — it runs in the browser you are reading this in.
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Background reading: Every PDF Tool You Need, and When to Use Each
Your PDF never leaves this device. Contracts, statements and applications are processed entirely in the browser — open the Network tab while you use the page and you will see no upload (how that works).
Disclaimer. Upload limits differ between portals and are often lower than the published figure once the whole application is counted. Check the limit shown on the upload screen itself. Full disclaimer.