Compress PDF
Reduce PDF file size while keeping quality
drag & drop a file anywhere · paste with Ctrl/⌘+V · max 100MB
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How To Compress PDF
Follow along with the steps below
Step 1
Upload your PDF
Select or drag the PDF file you want to shrink into the upload area. Any standard PDF works, whether it is a scanned document, a report, or an image-heavy file.
Step 2
Compress the file
The tool sends your PDF to a secure server that optimizes images and internal data to reduce the overall file size while keeping the pages readable.
Step 3
Download the smaller PDF
Once compression finishes, download your reduced-size PDF instantly. Check the new file size and reupload to compress further if you need an even smaller result.
Need to compress PDF files that are too large to email or upload? This free Compress PDF tool shrinks the file size of any PDF while keeping the document clear and readable. Just drop in your file and download a lighter version in seconds, with no sign-up, no watermark, and no software to install. It works in any browser on desktop or mobile, so you can reduce a bulky PDF anywhere and get past size limits without fuss.
Compress PDF online for free to reduce PDF file size for email attachments, web uploads, and portals with strict limits. This PDF compressor optimizes images and document data to make large PDFs smaller while keeping pages legible. There is no installation, no account, and no watermark on the output. Upload your document, let the secure server shrink it, and download the smaller PDF in moments from your phone, tablet, or computer.
What you can do with Compress PDF
- Shrink a PDF that exceeds an email attachment size limit so it sends without bouncing
- Reduce a large scanned contract or report to upload to a job portal or government form
- Compress an image-heavy brochure or portfolio for faster sharing and downloads
- Make course notes, slides, or ebooks smaller to save storage on your phone or laptop
- Fit a PDF under the upload cap on a website, CMS, or document submission system
A PDF often grows large because of high-resolution images, embedded fonts, and uncompressed page data, which makes it hard to email or upload within size caps. This Compress PDF tool processes your file on a secure server, optimizing its internal structure and images to cut the file size while preserving readable text and layout. It is completely free with no sign-up required and no watermark added. Your uploaded and compressed files are deleted within an hour, and the tool runs in any modern browser on any device.
Getting the most out of Compress PDF
Where the bytes actually go
Most PDF bloat lives in embedded raster images, not text. Ghostscript shrinks a file mainly by downsampling those images to a target DPI and re-encoding them, usually as JPEG. Vector graphics and text stay sharp because they are not pixels. So a scanned or photo-heavy PDF compresses a lot; a pure-text or vector file has little to give and may barely change.
DPI targets and why ratios vary
For screen or email, downsampling images toward 72-150 DPI is usually invisible and cuts size hard. Print needs around 300 DPI, which limits how far you can go before softening shows. A file that is already optimized, encrypted, or mostly vector text sees small gains. The result is governed by how many high-resolution images were inside, so no fixed ratio applies.
When a different tool fits better
This re-encodes images lossily, so use it for distribution, not archival masters. If a scanned page must stay searchable, OCR it first, then compress. Merging files or deleting pages is not what this tool does. For images you control, exporting the source at 150 DPI before building the PDF beats compressing a 600 DPI file afterward.
Server processing, privacy, and encrypted PDFs
Pick the lowest acceptable quality; over-compressing photos produces blocky JPEG artifacts you cannot undo. If size barely drops, the file is text or vector heavy, not a compression problem. Files run through Ghostscript on our server and your upload leaves your machine, though it is deleted within an hour. Encrypted or password-protected PDFs must be unlocked before Ghostscript can read them.
Compress PDF vs. the paid alternatives
Where this free tool holds up against the paid names — and where it doesn't.
Frequently Asked Questions
Will compressing a PDF reduce its quality?
The Compress PDF tool aims to keep your document clearly readable while making the file smaller. Image-heavy PDFs may show a slight reduction in image sharpness, but text and layout stay legible.
Is it safe to compress PDF files online?
Yes. Your PDF is processed on a secure server and your uploaded and compressed files are deleted within an hour, so they are not kept or shared.
How much smaller will my PDF get?
It depends on the file. PDFs full of high-resolution images often shrink the most, while files that are mostly plain text are already efficient and may reduce less.
Do I need to install software or create an account to compress a PDF?
No. The Compress PDF tool works entirely online with no download, no installation, and no sign-up required, and it is completely free. Your file is uploaded over a secure connection, compressed on our servers, and automatically deleted within an hour.
Will the compressed PDF have a watermark?
No. The tool adds no watermark and no branding to your compressed PDF, so you get a clean document ready to send or upload.
Can I compress a PDF on my phone or tablet?
Yes. Because it works in any modern browser, you can compress PDF files on a phone, tablet, or computer without any app.