PDF Compressor
A scanned document or an export full of high-resolution images can easily be tens of megabytes, too big for an email attachment or an upload limit. Compressing it trades some visual fidelity for a much smaller file.
The work happens in your browser: every page is rendered as a picture, saved as a JPEG and put into a new PDF, so text stops being selectable. That is what makes scans and photo PDFs much smaller, and it is why a mostly-text PDF may not shrink at all. The original never leaves your device, which matters when the document is a contract, an invoice or a medical record.
Runs in your browser. PDF Compressor processes your input on your own device. Nothing you enter or upload is sent to a server.
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(opens in a new tab)How to use the PDF Compressor
- Upload the PDF you want to compress.
- Choose a compression level: maximum, recommended, or light.
- Run the compression and check the reported size reduction.
- Download the compressed PDF.
Supported formats: PDF input; PDF output.
The three compression levels
Each level sets how sharply a page is drawn, in pixels per inch (ppi), and how hard the JPEG is squeezed. The page itself keeps its original size on the paper, so only the detail inside it changes. Maximum can leave small text a little soft, so check the result before you send it.
| Level | Detail and best use |
|---|---|
| Maximum | 72 ppi, JPEG 45%. The smallest file. |
| Recommended | 97 ppi, JPEG 65%. Most documents. |
| Light | 122 ppi, JPEG 82%. Best appearance. |
What gets smaller and what does not
Measured on a test file: a photo-heavy PDF
Input
3 pages, each one a large photographic JPEG, 4.20 MB
Output
Maximum 198 KB (95% smaller) Recommended 490 KB (89% smaller) Light 1.08 MB (74% smaller)
Measured on a test file: a text-only PDF
Input
12 pages of plain text, 3.0 KB
Output
Maximum 32 KB, Recommended 46 KB, Light 71 KB Every level made it larger, so the saving shows as 0%
- Scanned documents and photo-heavy PDFs are where the savings are.
- A text-only PDF is usually already small. Converting it to page pictures can leave it the same size or larger. The tool shows the new size and the saving, so compare before you download and keep the original if the new file is not smaller.
- Running the result through the compressor again redraws the pictures a second time and loses more quality, so choose the right level on the first pass.
If the file is still too big
- Try Maximum compression and look at the reported size.
- Send the document in parts: cut it up with Split PDF, then compress or send each part.
- If the PDF was made from photos, shrink the photos first with the Image Compressor or JPEG Compressor, then rebuild the PDF with Image to PDF.
- If you only need some of the pages, keep just those with Split PDF.
Things worth knowing
- Text and vector graphics are flattened to images, so the output is no longer selectable or searchable.
- There is no target-size setting, only three levels.
- Links, form fields and bookmarks are not kept.
- Password-protected and encrypted PDFs cannot be processed.
- Very large documents are limited by the memory available to your browser tab.
Frequently asked questions
Is my PDF uploaded anywhere?
No. The file is rendered and rebuilt in your browser with PDF.js and pdf-lib, so it never leaves your device.
Will the text stay selectable?
No. Compression works by turning each page into an image, so text becomes part of the picture. If you need selectable text, keep the original or use a tool that only restructures the file.
Why did the file barely get smaller, or even grow?
A PDF that is already mostly optimised text has little to squeeze, and re-encoding it as images can even add bytes. Try the maximum-compression setting, and expect the biggest gains on scans and image-heavy exports.
Can I compress a PDF to an exact size such as 100 KB or 1 MB?
No. There is no target-size setting, only three levels. Try the maximum level and read the size the tool reports. If it is still too large, split the file into parts with Split PDF and send them separately.
What do I lose when I compress a PDF here?
Every page becomes a flat picture. Text is no longer selectable or searchable, and links, form fields and bookmarks do not survive. The page keeps its original paper size and the output has the same number of pages.
Which PDFs shrink the most?
Scans and exports full of large photos. Their size comes from image data, which JPEG can reduce a lot. A PDF that is already mostly text and vector graphics is small to begin with, and turning its pages into pictures can make it bigger.