Compress PDF

Make a PDF smaller by recompressing its embedded JPEG images and removing unused data, with the text left untouched. Choose a strength or a target size.

Runs entirely in your browser. Your file is never uploaded.

Drag and drop files here, or choose files

How it works

Add the PDF. The tool counts the images inside it and tells you how many it can recompress.
Pick a strength, or enter a target size. Medium is the default.
Compress. The result is reopened with a second PDF reader and compared with your original before the download appears. If nothing got smaller, you are told and no download is offered.

What this tool changes and what it does not

It recompresses images stored as a single RGB JPEG, which is how scanners and phone cameras usually save a page. It can also shrink them to fewer pixels on the Strong setting and in the last steps of a target size.
It removes objects nothing in the file points to and repacks the file. Text, fonts, links, form fields and bookmarks are left as they are.
Images stored another way (PNG-style, CMYK, grayscale, masked, JPEG 2000) are left alone and counted in the result, so you can see what was skipped.
A file that is mostly text has little to remove and may not get meaningfully smaller. In that case the original is kept and no download is offered.
A digitally signed PDF is rewritten, so the signature stops verifying. The tool asks you to confirm before it does that. A password-protected PDF is refused.

How the target size works

The target is a maximum, and 1 KB is counted as 1,000 bytes. The result shows the exact size read back from the finished file.
The tool tries the tidy-only step, then lighter to stronger image settings, and stops at the first that fits. It never pads a file.
If the strongest step is still over the target, the result says so and shows the closest file it made. Do not upload a file that missed the limit. A scan with very many pages, or a file whose weight is not in JPEG images, may not reach a small target.

What was measured

Results below come from generated test files run in desktop Chrome, not from real-world documents, so treat them as an illustration and not a promise. A six-page scan of 6.2 MB became 3.1 MB on Medium and 578 KB on Strong. A mixed file of eight pages with four photos went from 1.3 MB to 522 KB on Medium and 1.1 MB on Light. A 79 MB, 15-page scan became 34 MB on Medium in about nine seconds. A text-only file had nothing to recompress and was kept as it was. Every output was reopened by two other PDF readers with the same page count, page size and text. Pixel differences on the Strong setting were visible in the measurements, so check the pages before you send them.

Good to know

Only images stored as a single RGB JPEG are recompressed. Other images (PNG-style, CMYK, grayscale, masked, JPEG 2000, fax-style scans) are left as they are and counted in the result.
Text, fonts, links, forms and bookmarks are not changed, so a file that is mostly text may not get meaningfully smaller.
A digitally signed PDF is rewritten, so its signature stops verifying. You are asked to confirm first.
Password-protected PDFs are refused.
If nothing gets smaller the original is kept and no download is offered.
Files over 100 MB or 300 pages are refused. The largest file measured was 79 MB and 15 pages, on a desktop computer; phones and tablets have not been measured.

Frequently asked questions

Will the text stay selectable?: Yes. Text, fonts and links are not changed; only images are recompressed. A scanned page with no text layer stays a picture, as it was.
Why did nothing get smaller?: The weight of some PDFs is not in JPEG images: it is in text, fonts, or images stored in other ways. This tool does not change those, so it keeps your original and says so instead of handing you a file that is no smaller.
Is the file uploaded?: No. The file is read and rewritten in your browser, and no request carries it. Your original file is never changed.
Can it reach an exact size such as 200 KB?: It tries to get under the target you enter, stopping at the gentlest setting that fits. If it cannot, it says the target was not reached and shows the closest result. It only recompresses images, so a target below the size of the text and fonts cannot be met.
Does compressing lower the quality?: Recompressing a JPEG loses some detail. Light and Medium keep every image's pixel size; Strong and the last target steps also reduce the pixel count. The result panel shows the average and largest pixel difference measured on the pages checked. Look at the pages before you use the file.
How do I know the new file is valid?: After compressing, the tool reopens the new PDF with a second reader and compares page count, page size, rotation and the text of every page with your original, and compares the picture of up to 40 pages. The download only appears if those checks pass.
What about a signed PDF?: Rewriting a signed PDF breaks its signature. The tool detects a signature and asks you to confirm before it continues. Use the original if the signature must stay valid.
How large a file can I use?: Up to 100 MB and 300 pages. The largest file measured was 79 MB and 15 pages on a desktop computer. Phones and tablets have less memory and have not been measured.
Can I stop it partway?: Yes. There is a Cancel button while it works. Nothing is downloaded and your original is unchanged.