PDF

Shrink a PDF file by recompressing its images

Only touches the images inside the document — a text-only PDF barely changes size, while a PDF of scanned pages usually shrinks a lot.

Drag a PDF here, or click to choose

PDF, up to 50 MB

Want to shrink a standalone image instead of a PDF? Use reduce image size. To merge several PDFs into one before compressing, use merge PDFs.

Local processing: your file never leaves your computer.

Does:Only touches the images inside the document — a text-only PDF barely changes size, while a PDF of scanned pages usually shrinks a lot.
Processes:Your PDF is processed entirely in your browser — nothing is uploaded to a server.
Doesn't do:Each recompressed image is compared against the original before replacing it: if the new version isn't smaller, that specific image is kept as-is. The same check applies to the whole file at the end of the process.

What actually makes a PDF heavy

A PDF isn't one uniform blob of data — it's closer to a set of drawing instructions plus whatever media is embedded in it. In the vast majority of real-world files, the instructions themselves (text, fonts, lines, drawn tables) take up very little space. What actually drives file size is the images embedded inside: scanned pages, screenshots, product photos, a signed contract that was scanned instead of signed digitally. A 40-page report with a dozen high-resolution photos can easily outweigh a 40-page report that's pure text by a factor of ten or more, even though both have the same number of pages.

This tool works on exactly that part. It recompresses the images embedded inside a PDF and leaves everything else alone: the text stays selectable and searchable, fonts stay embedded the way they were, and vector elements (lines, shapes, drawn tables) aren't touched — nothing gets turned into a flat image along the way, so nothing that was already sharp loses sharpness. Everything happens in your browser, so there's nothing to install and the file never leaves your computer.

Why the result varies so much from one file to the next

Because compression only acts on images, how much a file shrinks depends entirely on what's inside it. A plain-text contract or invoice, with no photos or scans, barely changes size — there's nothing there to compress. A PDF made of scanned pages, on the other hand, usually shrinks a lot, because each scanned page typically carries far more resolution than is needed to read the text on it. There's no way to promise a percentage of reduction ahead of time: two PDFs of the same starting size can behave completely differently here, depending only on what they carry inside.

What gets recompressed, and what's deliberately left alone

Not every image inside a PDF can be safely recompressed in a browser. This tool handles two cases: photos already saved as JPEG inside the PDF, and raw grayscale or plain RGB images. Between them, these cover the large majority of images found in everyday PDFs.

Deliberately left out: CMYK images (common in files that came from a print production workflow), images using an indexed color palette, specific ICC color profiles, JPEG 2000 compression, and the fax-style compression used by some older scanners. Handling those formats with a simplified approach would risk shifting the image's colors or corrupting it outright — a worse outcome than just leaving that particular image as it was. Before processing anything, the tool shows how many images it found in total and how many can actually be recompressed in this browser; if none can, it says so immediately, instead of making you wait through a full run only to find out there was nothing to gain.

Three levels, and a preview to help you decide

Compression strength has three levels — light, medium, and strong — each one trading more image quality for a smaller file. Because this is lossy compression (the images genuinely lose detail, the same idea as lowering a photo's quality setting), the tool shows a side-by-side preview of one real page from your document, before and after, updated as you switch levels. That preview is what lets you judge whether the loss is acceptable before generating the whole file, instead of finding out only after processing everything.

When compressing just isn't worth it

Sometimes a PDF's images already arrive well compressed, and reprocessing them saves next to nothing — in some cases the result can even end up larger than the original. The tool compares the final size against the original before handing anything over: if the reduction is too small to be worth it, or the file would come out larger, it gives you the original PDF back unchanged, rather than a result that isn't actually an improvement.

What this tool doesn't do

It doesn't rasterize any page — the content stays a real PDF, not a photo of each page. It doesn't remove a password from a protected PDF; a file like that is detected on upload and isn't processed. It doesn't recognize or interpret the text on the pages — this isn't an OCR tool. And it doesn't change the content of any page beyond recompressing the images that were already there — no text, shape, or element is added, removed, or moved.

Frequently asked questions

What exactly gets smaller in a compressed PDF?

Only the images embedded in the document — photos, scanned pages, screenshots. The text, fonts, and vector elements (lines, shapes, drawn tables) aren't touched and don't change size. That's why a plain-text contract barely shrinks, while a PDF of pages scanned as photos can shrink a lot.

Why didn't my PDF shrink much?

A few common reasons: the file has no images (the size comes from text, fonts, or internal structure); the images were already well compressed; or they use a color format this browser can't safely recompress, like CMYK or an indexed palette — in those cases the tool tells you before processing, so you're not left waiting for a result that won't come.

What's lost when a PDF's images are compressed?

Fine detail in the images, proportional to the level you pick: light changes little, strong can make edges and scanned text visibly softer. It's lossy compression, the same idea as lowering a photo's quality — the side-by-side preview shows the effect before you generate the full file, exactly so you can judge it first.

Some images in my PDF weren't compressed. Why?

The tool only recompresses images in formats it can safely decode in the browser: plain JPEG and raw grayscale or RGB images. Images in CMYK, with an indexed color palette, in JPEG 2000, or in fax compression (common on older scanners) are left out — handling those formats incorrectly could corrupt the image, which is worse than simply not compressing it. The result shows how many images were skipped and why.

Can the compressed file end up larger than the original?

In theory, yes, if the images were already well compressed — which is why the tool compares the final size against the original before handing anything over. If the result would be larger, or the reduction is too small to be worth it, it delivers the original file unchanged instead of a worse or only marginally different one.