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Compress PDF

Drop a PDF to cut its size. Only photos and scans are recompressed, so text and graphics stay crisp. Your PDF is processed on your device and never uploaded.

On-device・No upload

Your files and input are processed only inside your browser on this device and are never uploaded to our servers.

Drop files here (multiple allowed)

or

PDFs are processed in this browser on your device and never uploaded.Accepts: PDFUp to 300 MB per filePaste (Ctrl+V) also works
Compression settingsStandard (recommended)
Compression level

Big savings with quality that looks the same on screen. For email and uploads.

How to use

  1. Drop PDFs or click “Choose files” (multiple allowed). Compression starts right away with the “Standard” level.

  2. Check the original size, new size, savings and number of recompressed images in the list.

  3. For a smaller file, switch to “Smallest” or Custom under “Compression settings” and click “Recompress with these settings”.

  4. Download the PDF (or all files as a ZIP).

What it does

PDF compression without uploading

Most online compressors send your PDF to their servers. LIBRA Works compresses entirely in your browser (Web Workers + WebAssembly), so contracts and personal documents never leave your device.

Text and graphics stay sharp

Only photos and scanned images — the bulk of most file sizes — are recompressed with MozJPEG and downscaled if needed. Text, lines, shapes and fonts are untouched and remain searchable.

Fragile images are skipped automatically

CMYK and special colour spaces, masks, and low-colour images like charts or screenshots would look worse as JPEG, so they are left as they are.

Never makes files bigger

Already-optimised PDFs may not shrink further. In that case the original file is returned unchanged.

Removes dead weight

Embedded page thumbnails, XMP metadata and unreachable leftovers from incremental saves are removed too.

Use cases

  • Fit a PDF under an email attachment limit (e.g. 10 MB)
  • Meet the upload limit of an application or submission portal
  • Shrink PDFs of documents scanned or photographed with a phone
  • Make photo-heavy catalogues and brochures easier to share
  • Compress confidential documents without uploading them to an online service

Supported formats

Input

PDF (.pdf)

Output

PDF (.pdf)ZIP (multiple files)

Capability matrix

FeatureSupportNotes
Recompress and downscale photos/scansSupportedJPEG and Flate (8-bit RGB/gray) images
Keep text, vector graphics and fontsSupported—
Three levels + custom (quality, max size)Supported—
Convert photos to grayscaleSupported—
Batch compression and ZIP downloadSupported—
Compress CMYK / special colour space imagesNot supportedLeft unchanged to avoid colour shifts
Font subsetting / recompressionNot supported—
Target a file size (e.g. under 1 MB)Not supportedUse the “PDF Target Size” tool
Password-protected PDFsNot supportedRemove the protection first

Limits & notes

  • Up to 300 MB per file; files are processed one at a time.
  • PDFs made mostly of text and vector graphics are already compact and barely shrink.
  • Bookmarks, links and forms are kept, but conformance to standards such as PDF/A may not be preserved.
  • Always check the result — “Smallest” can make photos look rougher.

Privacy & safety

Reading, compressing and saving all happen inside your browser. Your PDF is never sent to or stored on a server. Only the compression engine (WebAssembly) is downloaded the first time.

FAQ

Will text become blurry?
No. Only photos and scanned images are recompressed; text, lines and shapes stay as they are. For scanned documents the text is part of the image, so choose “High quality” to keep it easy to read.
How much smaller will my PDF get?
PDFs with many photos or scans often shrink by 50–90% at “Standard”. Text-only PDFs are already small and may barely change. You can see the result for each file in the list.
Is my PDF uploaded?
No. Compression runs entirely in your browser; your PDF never leaves your device.
Why didn’t my PDF get smaller?
Text-heavy or already-compressed PDFs often cannot be reduced further, so the original is returned. If a photo-heavy PDF doesn’t shrink, its images may use CMYK or other colour spaces we leave untouched.
Does it work on phones?
Yes, in iPhone and Android browsers. Large PDFs use a lot of memory, so a computer is recommended for those.

Related tools

Images to PDF

Drop images, put them in order and get one PDF. Choose page size, orientation and margins; phone photos are rotated correctly. Images are converted on your device and never uploaded.

PDF Editor

Lay text (Japanese included), shapes, arrows, a highlighter, freehand drawing and images on top of a PDF, and fill in its form fields. Everything is written as PDF vectors and real text, never as a picture. Rewriting the original text and true redaction are not possible.

PDF Extract

Take the text, images, links, attachments, form values and bookmarks embedded in a PDF, for the pages you choose. Images stay as embedded (JPEG untouched). Your PDF never leaves your device.

Extract PDF Pages

Gather just the pages you need from one or more PDFs into a single PDF (or one PDF per source file in a ZIP). Pick by thumbnail, range or text search, and leave out blank pages automatically. Your PDFs are processed on your device and never uploaded.

Merge PDF

Drop several PDFs, put them in order, and get one PDF. You can also choose which pages to take from each file. Nothing is uploaded — merging happens on your device.

PDF Metadata Cleaner

Before you share a PDF, see and remove the hidden personal data in it: author name, comment authors, attachments and more. Compare items before and after, and process many files at once. Nothing is uploaded.

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