Compress PDF
WEBCompress a PDF to a smaller file size while keeping it readable — free and right in your browser. Nothing is uploaded.
What is the Compress PDF tool?
Compress PDF shrinks a PDF's file size so it's easier to email, upload to a form, or store — without sending the file to a server first. Unlike most online PDF compressors, the whole job runs inside your browser: contracts, scans and reports never leave your device. There is no sign-up, no watermark and no file limit, and the tool is completely free.
Pick from three honest compression levels instead of a single black-box button. Lossless runs a real structural optimization that never touches image or text quality — a safe default for any document. Strong re-renders image-heavy pages at a smaller size for a much bigger reduction with only a small, usually invisible quality trade-off. Extreme goes further still for scan-like PDFs where file size matters more than pixel-perfect sharpness. A live before/after size estimate updates as you pick a level, so you always see the trade-off before you download.
Because everything happens on-device, you can compress a PDF from your phone just as easily as from a desktop — no app to install, no account, and the compressed file downloads straight to your device the moment it's ready.
How to use the Compress PDF
- Open the PDF you want to shrink — drag it in, pick it from your device, or choose a recent file.
- Pick a compression level: Lossless, Strong or Extreme.
- Check the live before/after size estimate to see how much smaller the file will get.
- Export the compressed PDF — the whole job runs in your browser; nothing is uploaded.
- Download the smaller file to your device.
Frequently asked questions
Does compressing a PDF reduce its quality?
It depends on the level you pick. Lossless never touches image or text quality — it only strips redundant structure. Strong and Extreme re-render image-heavy pages at a smaller size, which trades a small (often invisible) amount of sharpness for a much bigger size reduction — you see the estimate before you export, so you can compare.
Is there a file size limit?
No hard cap. Because compression runs on your device, the practical limit is your browser's available memory rather than a service quota — most real-world documents compress without any issue.
Is it safe to compress a PDF online?
Yes — with Carbide your file is never actually sent anywhere. Compression happens entirely in your browser, so no server or third party ever sees the document, unlike upload-based compressors that process your file on their own infrastructure.
Which compression level should I use?
Start with Lossless for anything you want to keep pixel-perfect. If the file is still too big — say, for an email attachment limit — move to Strong, and reserve Extreme for scanned documents where a smaller file matters more than sharpness.
Can I compress a scanned PDF?
Yes, and scanned PDFs are exactly where Strong or Extreme help the most, since scans are usually just large images per page — re-rendering them at a smaller size can cut the file down dramatically.