PDF compressor
Compress PDF Online
Reduce a PDF's file size to a limit you choose, and see the measured size before you download.
- Runs in your browser
- No upload or account
- Files up to 100 MB
Your file never leaves this device — everything happens locally in your browser.
Compressing more than one PDF? Try batch compression.
Target size
Starting…
Processing happens entirely on this device — nothing is uploaded.
Your file never leaves this device — everything happens locally in your browser.
Your file never leaves this device — everything happens locally in your browser.
How it works
How to compress a PDF
Choose your PDF
Drop it on the compressor or browse for it. It opens in this browser tab; nothing is uploaded.
Set a target size
Pick a preset from 100 KB to 2 MB, or type your own limit in KB or MB.
Let it find the best fit
The tool tries several quality levels and keeps the highest one that fits, not the smallest file it can make.
Check the size, then download
The result shows the measured size. The download keeps your file's name with “-compressed” added, so the original stays untouched.
Under the hood
What happens to your PDF
They run in this order. The third only happens to image-heavy files that still don't fit.
Size check
Every fileIf the file is already at or under your target, it's left untouched and the tool tells you so.
Rebuild and re-encode
Every attemptEach attempt drops unused objects, repacks the file's structure, and re-encodes photos and scans as JPEG. A PDF with no images is only repacked, so nothing on the page changes.
Pages as images
Last resortFor image-heavy files that still don't fit, pages can be turned into compressed images. Text stops being selectable, and the result screen says so.
Limits
What the compressor can handle
- File size
- Up to 100 MB per PDF.
- Files per run
- One. For several at once, use batch compression.
- Passwords
- Password-protected PDFs aren't supported. Remove the password first.
- Time
- After about 45 seconds the tool starts no new attempts and gives you the best result so far. One attempt on a very large file can take longer.
- Your device
- Processing uses your device's memory, so very large files may be too much for an older phone.
Troubleshooting
If something goes wrong
“Couldn't quite reach” your target
Try a larger target, or read why some PDFs won't compress any smaller.
“We couldn't read that file”
The file is damaged or isn't really a PDF. Export it again from the program that made it.
Text is no longer selectable
The target was only reachable by turning pages into images. A larger target keeps the text.
An older Chinese, Japanese, or Korean PDF stops early
Some of these use fonts the browser can't draw. The tool won't turn their pages into images, because the text would be lost, so it may stop above very small targets.
FAQ
Frequently asked questions
Will the text in my PDF still be selectable after compression?
Yes, unless the only way to reach your target is to turn pages into images. That's a last resort, used only for image-heavy files when re-encoding their images can't get small enough. When it happens, the result screen tells you the text is no longer selectable, so you can choose a larger target instead.
What will the compressed file be called?
Your original name with “-compressed” added — report.pdf downloads as report-compressed.pdf — so you can keep both versions side by side.
Can I stop a compression that's taking too long?
Yes — press Cancel while it runs. The search also stops on its own: after about 45 seconds it starts no new attempts and gives you the best result it found. On a very large file, a single attempt can take longer than that.
Why did the tool say my file didn't need compressing?
It checks the file's real size first. If it's already at or under your target, it doesn't touch the file and tells you so — there's nothing to gain from recompressing it.