Most of a large PDF is usually pictures, such as scanned pages or photos. This tool recompresses those pictures as JPEG where that makes them smaller, and tidies the file's structure. You cannot choose a quality or a target size such as "under 1 MB". If the recompression cannot make the file smaller, you get your original back unchanged, never a bigger file. Here is what it did on test PDFs, including a case where it does almost nothing.
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Overview
About Compress PDF
What the tool does
It runs qpdf with image optimisation on: images in the PDF are recompressed as JPEG only where that makes them smaller, and the page content streams and objects are compressed. The JPEG quality is qpdf's own setting and cannot be changed here. Image dimensions are not changed, so there is no downsampling to a lower resolution. The page count stays the same and text stays text: the first line of a compressed test page was still readable text. If the result is not smaller than the upload, you receive an unmodified copy of the original.
Measured examples
| Generated test PDF | Before | After | Change |
|---|---|---|---|
| 10 pages of text only | 7.6 KB | 6.4 KB | -16% |
| 3 pages showing the same 2400 × 1600 JPEG, saved at quality 95 | 1.46 MB | 1.46 MB | -0.02% |
| 3 pages showing the same lossless (PNG-style) 2400 × 1600 image | 5.15 MB | 1.22 MB | -76% |
Generated locally; not a benchmark; not a guaranteed result. These were measured on this site's server. The big saving came from the last row: images stored without loss, which is how screenshots, line art and some scans are saved, were converted to lossy JPEG. On such pages, thin lines and small text inside the pictures can look rougher afterwards, so zoom into the compressed file before you throw the original away. The middle row shows the opposite case: a JPEG that is already compressed, even at a high quality setting, was left almost untouched, so a PDF full of ordinary camera JPEGs may barely shrink. Results can also differ between versions of qpdf.
Which PDFs will barely change
A PDF that is mostly text, that already contains compressed JPEG images, or that has few images has little to gain. The tool then returns a result close in size to the original, or the original itself. PDFs built from lossless images, which includes many scans saved as PNG and screenshots, shrink the most. For an image-heavy PDF that is still too large, the options are to reduce the page images before building the PDF, for example with the Image Resizer and Image to PDF, or to drop pages you do not need with Extract PDF Pages.
What this tool does not do
It does not aim for a target size, offer low / medium / high levels, reduce image resolution, remove embedded fonts or metadata, or make scanned pages searchable. The limits are 20 MB and 200 pages, and a PDF that needs a password to open is rejected. To see what is in a file before you compress it, use PDF Information or the PDF Image Extractor.
Compatibility
Supported Formats
Accepts PDF files up to 20 MB and 200 pages, identified by their contents. The result is a PDF with the same number of pages. Password-protected PDFs are rejected.
Guide
How to Use Compress PDF
- Choose a PDF file (up to 20 MB and 200 pages).
- Click "Compress PDF". The page shows the size before and after.
- Download the result and zoom into a page with images to check it looks acceptable before you replace the original.
Highlights
Features
- Never larger than the original If recompression does not make the file smaller, you get your original file back unchanged.
- Image-focused Images are recompressed as JPEG where that makes them smaller; page content and text are kept as text.
- Before and after shown The page reports both sizes so you can see what changed.
Applications
Use Cases
- Shrinking a scanned document before emailing it
- Getting a photo-heavy PDF under an upload limit
- Reducing a PDF exported from a presentation or design tool
Good to Know
Limitations
Settings are fixed: no quality choice, no downsampling, no target size and no levels. Lossless images in the PDF can be converted to lossy JPEG, which may roughen fine detail. A PDF that is mostly text, or whose images are already compressed JPEGs, may shrink very little or not at all, in which case you receive the original. Password-protected PDFs are rejected.
Files are processed on our servers and are not shared with third parties. Files are deleted as soon as processing or download finishes. Any leftover temporary file is removed automatically by our cleanup process within the configured retention period (60 minutes). See our Privacy Policy for full details.
Support
Frequently Asked Questions
Can I compress a PDF to under 1 MB or another exact size?
No. There is no target size and no quality setting. The tool recompresses images as JPEG where that helps and reports the result. If it is still too big, try reducing the images before they go into the PDF, or keep only the pages you need.
Why did my PDF barely get smaller?
Mostly text, images that are already compressed JPEGs, and few images all leave little to save. Our text-only test file went from 7.6 KB to 6.4 KB, and a PDF of high-quality JPEGs stayed the same size.
Can the result be bigger than my original?
No. If compression does not make the file smaller you get the original file back.
Will the quality of my scans suffer?
It can. Images are recompressed as JPEG, which may be noticeable on fine detail. Lossless images, such as screenshots, were converted to lossy JPEG in our test, so zoom in on the result. Resolution is not reduced.
Does compressing remove or change the text?
No. Page text stays text and stays selectable; only images and the file's structure are recompressed.
Keep Going
Related Tools
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