PDF Compressor
Shrink a PDF by compressing its embedded images. Everything runs in your browser, so your files stay private.
This tool reduces image resolution inside the PDF. It is not a full PDF optimizer: vector content, fonts, and structure are unchanged.
Choose a PDF and press Compress PDF to see your results.
Privacy: your file is processed entirely in your browser. Files never leave your browser.
Need to compress PDF files that are too large to email or upload? This free tool reduces your PDF size in seconds, right in your browser. Upload your file, choose a compression level, and download a smaller PDF that fits email attachment limits and upload forms. No signup, no watermark, and your files never leave your device.
Big PDFs are a daily annoyance. Gmail and most email providers reject attachments over 25 MB, job portals cap resume uploads at 2 to 5 MB, and course platforms often limit file submissions to 10 MB. A scanned contract, a photo-heavy report, or a slide deck exported at print quality can easily be 30 MB or more. Compressing the PDF shrinks it to a shareable size without changing the content, page count, or layout. Our compressor is ideal when you need to send documents quickly: contracts by email, assignments to a portal, or reports through a messaging app.
How to Use the PDF Compressor
- Upload your PDF. Drag and drop the file into the compressor, or click to browse your device. It is read locally, never uploaded.
- Choose a compression level. Pick a stronger level for the smallest file, or a lighter level when you want to keep images as sharp as possible.
- Download your smaller PDF. Click compress and download the result in seconds. Compare the old and new sizes before you send it.
How It Works
This compressor runs entirely in your browser using a local PDF library. It reduces file size by recompressing the images embedded in your PDF at a lower quality setting, which is where most of the bytes in a large PDF live. A photo scanned at print quality, for example, can be re-encoded at a web-friendly quality and become several times smaller while remaining perfectly readable on screen.
Here is the honest part you should know before you compress: compression reduces the quality of embedded images in your PDF, and this tool is not a full PDF optimizer. It shrinks image data, but it does not remove unused fonts, deduplicate repeated objects, flatten layers, or restructure the file the way a desktop optimizer would. That means results vary by document: image-heavy PDFs shrink dramatically, while text-only PDFs with little image data may barely shrink at all. If a file shrinks less than you hoped, it is not broken, it simply has little image data to reduce.
A Worked Example
Take a 22-page project report exported from a design tool at print quality: 34 MB, too big for email. You upload it and choose the recommended compression level. The tool recompresses the report’s full-page images and charts at a lower quality and the file drops to 6.8 MB, an 80 percent reduction, small enough to attach to an email. You open the result and check a photo page: at normal screen size it looks nearly identical to the original, with only slight softening visible when zoomed in to 200 percent. The text, tables, and page order are unchanged. Total time: about 15 seconds.
Compress PDF FAQ
How much can I reduce my PDF size?
It depends on the document. Image-heavy PDFs such as scanned reports or photo decks often shrink by 60 to 90 percent. Text-only PDFs with few images may shrink only slightly, because there is little image data to reduce.
Will compression change my document’s content?
No. Compression does not remove pages, alter text, or change the layout. It only reduces the quality of embedded images, so the document reads exactly the same, with slightly softer images at high zoom levels.
Is it safe to compress confidential documents?
Yes. The entire process runs 100% in your browser. Your PDF is never uploaded to a server, so contracts, medical records, and financial documents stay private on your device.
What if my PDF is still too large after compression?
Try a stronger compression level, which trades more image quality for a smaller file. If the document is text-heavy and barely shrinks, a full desktop PDF optimizer may be needed, since this tool reduces image data rather than restructuring the file.
Can I compress scanned PDFs?
Yes, and scanned PDFs are often the best candidates, since they are essentially collections of page images. A 40 MB scan can commonly drop under 10 MB while remaining easy to read on screen.
Is the PDF compressor free?
Yes. It is free with no signup, no watermark, and no limits on how many PDFs you compress.
More Free Tools
If your PDF came from images and you want the originals instead, use pdf to jpg to extract pages as images. To combine a compressed file with other documents, try merge pdf. And if your images are too large before you even make the PDF, compress image shrinks them first.