Compress PDF Files Online for Free

This tool renders each page of your PDF to a JPEG image at a resolution and quality you choose, then rebuilds a new PDF from those images. That makes it lossy compression: the size reduction is real and permanent, achieved by lowering image detail rather than by reorganizing data. It is the same approach the big services fall back to for image-heavy files, and the whole process runs in your browser with pdf.js and jsPDF.

A scanned document is already just a photo of each page, so re-encoding those photos at a smaller size loses nothing you had and often cuts the file by 40 to 80 percent. The same is true for photo-heavy reports, brochures, and presentations. If your PDF is mostly images, this is the right tool and the savings are the biggest.

Because every page becomes an image, selectable and searchable text is flattened into that image. After compression you cannot highlight text, copy it, or find it with Ctrl-F, and forms and links stop working. On a scan that costs nothing, since there was no live text to begin with. But if you have a text document you need to keep as text, this is not the method to use. A lossless optimizer, which reorganizes data without touching your text, is the better choice there.

A single slider sets the compression strength from 0 to 100 percent. Drag it, or tap a preset to jump there. Behind the slider are the two real knobs: JPEG image quality runs from 90 percent at the lightest end down to 30 percent at the strongest, and pages are re-rendered between 150 DPI and 100 DPI. That 100 DPI floor is deliberate, because below it scanned text stops being readable and the file is no longer worth having. Higher strength means a smaller file with softer images, and how much smaller depends entirely on the PDF, which is why the slider sets the strength rather than a promised size.

Compressing earns its keep whenever a file is too big for where it needs to go. The most common reasons:

Add your PDF, choose a compression level, and click Compress. The smaller file is ready to download in a few seconds. It all runs in your browser, so the file is never uploaded.

No, and it is worth being clear about that. This tool re-encodes each page as a JPEG image, so the size reduction is real and permanent, and images get softer as you compress harder. If you need identical quality with selectable text preserved, this is not the right method. Where it shines is scanned and image-heavy PDFs, where a smaller image is exactly what you want.

No. Because every page is turned into an image, live text is flattened into that image. You will not be able to select it, copy it, or search it with Ctrl-F afterward. On a scanned document that is no loss, since scans have no selectable text to begin with. On a text document you want to keep as text, use a lossless optimizer instead.

Scanned documents and image-heavy files. A scan is already just a picture of each page, so compressing the image loses nothing you had and can cut the size dramatically. Photo-rich reports and presentations also do well. Plain text documents are the wrong fit, because their text is already tiny and turning it into an image only makes things worse.

It depends on the content and the level you pick. Scanned and image-heavy PDFs commonly drop 40 to 80 percent. Files that are already optimized may barely shrink, and if a compressed version would end up larger, the tool tells you so instead of handing you a bigger file.

No. The entire compression runs in your browser, so your PDF never reaches a server. You can confirm it: open your browser's developer tools, switch to the Network tab, and run a compression. You will see it make no network requests for your file at all.

Yes, and it is a common reason to use this. Gmail caps attachments at 25MB and Outlook at 20MB, and email encoding adds roughly 30 percent overhead on top of the file, so aim well under those numbers. For a scanned document, Medium or Strong usually gets you there.

Not to an exact number yet. Drag the compression slider toward the stronger end for the smallest file, and the result card shows the size you landed on so you can nudge the slider and try again. If it still will not fit a hard cap like 100KB, the file is likely text-heavy or very high resolution, which an image-based compressor can only shrink so far.

Yes. It runs in any modern browser with no app to install, so you can compress from a phone, tablet, or desktop. iPhone and Mac also have built-in options (Files and Preview), but this gives you more control over the quality and keeps the file entirely on your device.

Not directly. If a PDF needs a password just to open, remove that password first with an unlock tool, then compress the unlocked file.

It is free with no account, no email, and no watermark. Compress as many files as often as you like. Nothing is stamped onto your pages.