Compress PDF
Shrink a PDF by re-saving only the photos inside; text stays searchable. Runs in your browser with no upload.
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Compress PDF: complete guide
Walk through the steps and examples, or jump straight to the topic you need.
At a glance
- Input
- One PDF, up to 30MB. Password-protected PDFs cannot be opened.
- What gets reduced
- Only JPEG photos in the document and lossless photos with many colors (like PNG) are re-saved. It looks at up to 300 per document.
- What is left alone
- Text, shapes, tables, images with transparency, palette or CMYK images, and images with simple colors such as charts and screen captures are not touched.
- Quality levels
- Best quality shrinks to 2,400px on the long side, Balanced to 1,600px and Smallest size to 1,200px. It never enlarges beyond the original.
- Saving
- If it did not shrink or shrank by less than 1%, there is no save button. The original is not changed, and a new file with "-compressed" added after the name is made.
How to use Compress PDF
Drop the PDF to compress
Drag the file into the "Drop the PDF to compress here" box or choose it. The file size and "n re-savable images" are shown right away.
Choose the quality
Choose from Best quality, Balanced and Smallest size. For documents you will print, Best quality is right, and for documents you will email, Balanced fits. Changing the quality clears the previous result.
Press Compress
The button shows "image n of total" as it works. If it takes long, you can press Stop to halt it.
Look at the result and save
Check the original and result sizes, the percentage reduced and the number of photos re-saved, then press "Save compressed PDF". If there is no save button, it is better to keep using the original.
What it’s good for
Which documents get smaller?
Documents that contain photos or scanned images get smaller. Documents with only text, tables and shapes are already small and have nothing more to reduce. When you add a file, it first shows how many photos can be re-saved, so you can judge before running it.
Text is left as it is
It does not bake whole pages into pictures. It picks only the photos inside the document and re-saves them, so text stays as text. Copying, searching and screen reading still work in the result file.
Worked examples
Reducing the size of a large photo
Photo in the document 4000 x 3000px
Quality: Balanced / Best qualityBalanced: 1600 x 1200px
Best quality: 2400 x 1800pxA document with many photos
Original 12,000,000 bytes
Result 4,200,000 bytes · 8 photos re-savedReduced by 65%
Re-saved 8 photos and reduced the size by 65%. Text and shapes are unchanged.A document that barely shrank
Original 5,000,000 bytes
Result 4,980,000 bytesReduced by 0.4%
The size dropped by less than 1%. You are better off keeping the original.Choosing a quality level
Swipe the table sideways to see the rest.
| Quality | Long side limit | Suited for |
|---|---|---|
| Best quality | 2,400px | Documents you will print or zoom into |
| Balanced | 1,600px | Documents viewed on screen and sent by email |
| Smallest size | 1,200px | Documents with a tight submission size limit. Photos may look blurry. |
When the result isn’t what you expected
The Compress button cannot be pressed
If you see "This document has no images that can be re-saved", the document has only text and shapes, or only images that must be left as they are. It cannot be reduced this way.
It says the PDF is password-protected
You need a copy with the password removed. If you know the password, remove it first with the PDF password tool and then add it again.
It says the file is too large
PDFs over 30MB are not accepted. Split the pages with Split PDF and then compress each.
Fewer photos were re-saved than the number of photos
Photos that would get larger than the original after re-saving are skipped. Lossless photos are converted to JPEG only when they shrink by more than 20%, so the "n of total" in the result can differ.
Key terms
- Re-saving (recompression)
- Decoding a photo once and saving it again as JPEG at a set quality. The photo quality may drop a little in the process.
- Lossless image
- An image saved without losing quality, like PNG. It is converted to JPEG only when it has many colors, like a photo.
- Long side
- The longer of a photo's width and height. Each quality level sets a limit for this length.
Compress PDF FAQ
Does the text get blurry after compressing?
No, because text and shapes are not touched. Only photos are re-saved, and how sharp the photos look depends on the quality level.
The size did not shrink at all.
The document has no photos or is already optimized. In that case it does not say it shrank and does not show a save button. Use the original.
Does the original change?
No. It only creates a new file, and the document you added stays as it is.
Do scanned PDFs get smaller?
Scans have a picture on each page, so they tend to suit it well. However, images that are not JPEG, lossless RGB or gray, such as black-and-white fax-style compression, are left as they are.
What happens if I stop partway?
If you press Stop, it says the compression was stopped and no result file is made. The original is untouched, so you can change the quality and try again.