LooPDF

Compress PDF File

Reduce the file size of your PDF. Note: Basic compression is available. For best results, consider using specialized compression tools.

Drop PDF file here or click to browse
Select a PDF file to compress
Compress PDF

Compress PDF files where the weight is

In a large PDF, most of the bytes are usually pictures: scanned pages, photos, screenshots pasted into a report. Text and line drawings take up little room next to them, which is why Compress PDF concentrates on the images to decrease PDF size where it matters most.

Text, vector drawings and the page layout come through every level looking the same, so words stay sharp and selectable, and pages keep the orientation they had. What the three levels change is how much detail the images keep.

Compression levels

How far each level can shrink PDF size

  • High Compression

    High-resolution color and gray images are resampled to 96 dpi, and photos get the strongest JPEG compression. For strict size limits and reading on screen.

  • Medium Compression Default

    Images are resampled to 150 dpi, which stays clear on phones and laptops, and photos get moderate JPEG compression.

  • Low Compression

    Images keep the most detail of the three levels and get the lightest JPEG compression. The one for anything you will print.

Worried about losing quality?

Our guide shows why a PDF is large, which level suits which document, and what to do with scans.

How it works

What happens to your file

Every file goes through two passes. The first drops objects that no page uses and repacks the internal data, leaving the images exactly as they were. The second rebuilds the whole document at your level: fonts are cut down to the characters in use, an image repeated on several pages is stored once, and images are resampled and recompressed to minimize PDF size.

Both results are measured against your upload, and the smallest of the three is the one you get, so the download is never larger than the original. With Remove document metadata ticked, the author, title and app details, including the embedded XMP block, are then cleared from that file.

Several files are compressed one after another with the same settings. The result lists every file with its new size and a download of its own, and bundles the ones that worked into a single ZIP.

How to

Reduce PDF file size in three steps

  1. Drop in your PDFs

    Drop one or more PDFs onto the dropzone, or click it to browse your files.

  2. Set the level

    Choose it under Compression Level and decide whether to tick Remove document metadata.

  3. Compress and download

    Click Compress PDF to see the original size, the new size and the reduction, then save the result.

When it helps

Where file size limits get in the way

  • Email attachments

    Mail services cap the size of attachments, and a long scan can be well over the limit.

  • Upload portals

    Job, visa, school and tax portals often accept only a few megabytes per file.

  • Phone scans

    Scanner apps save each page as a full-size photo, with far more detail than reading on screen needs.

  • Shared folders

    Smaller files take less space in cloud storage and download sooner for everyone who opens them.

  • Course submissions

    Schools and universities often cap assignment uploads, and a report full of photos or scanned pages can go over it.

  • Record archives

    Folders of scanned statements, receipts and letters take up less room once their pages are resampled.

PDF grew after many edits?

Optimize PDF explains what piles up inside a file through repeated edits and saves, and clears it out.

Compress PDF questions

loo, the LooPDF mascot, with question marks

Still stuck? Contact us

It depends on what the file holds. Scans and photo-heavy documents shrink the most, because their images carry most of the weight. A PDF that is mostly text is small already and has little to give.

Its images were probably small or heavily compressed already, or there are only a few of them. Try High Compression if you haven't; if that saves little too, the file has little left to remove.

Split it into parts with Split PDF if the recipient accepts several files, or take out pages nobody needs with Delete Pages. Photo appendices and scanned attachments are usually the heaviest pages.

Only slightly. Author, title and app details take up little space, so tick it to keep those details out of a file you share rather than to save bytes.

Each file keeps the name you uploaded it with. A batch ZIP is named after the number of files, such as compressed-pdfs-3.zip, and two files that share a name are numbered inside it so neither is lost.

The others are still compressed. The failed file stays in the list with the reason next to it, and the ZIP holds only the files that worked.

Yes. Pure black-and-white images, which many document scanners produce, are thinned out by keeping every so many pixels rather than blending them, so lettering keeps hard edges. On High Compression they go to 120 dpi instead of 96, and on Medium Compression to 150 dpi.

No. A ZIP has to be unpacked before the PDF inside can be read, and PDFs barely shrink in one. Compress PDF makes the PDF itself smaller, so it opens as usual.