PDF Compressor

Make PDFs smaller without giving up selectable text

The PDF Compressor shrinks bloated PDFs — phone scans, bank statements, brochures and reports full of photos — so they fit email limits and upload forms. Most of a large PDF's weight is in its images, so the tool decodes each photo or scan, scales it down to the resolution the page actually needs and re-encodes it with MozJPEG, a highly efficient JPEG encoder that runs in your browser as WebAssembly.

Everything else is tidied losslessly: duplicate images and fonts are merged, leftover objects from earlier edits are dropped, hidden XMP metadata and page thumbnails are removed, uncompressed streams are deflated and the file is saved with compact object streams. Text, fonts and vector drawings are never turned into pictures, so the compressed PDF stays searchable and selectable. An image is only replaced when the new version is genuinely smaller, and if the whole file wouldn't shrink you get your original back.

All of this happens on your device. Files are read into memory, processed in a background Web Worker so the page stays responsive, and handed back as downloads; nothing is uploaded. That makes it suitable for confidential paperwork, and it also works on a phone or tablet.

Why use PDF Compressor?

Real size savings

Images are downsampled to a sensible DPI and re-encoded with MozJPEG for big reductions on scans and photos.

Text stays text

Fonts and vector content are untouched, so the result is still searchable and selectable.

Never bigger

If compression wouldn't help, you get your original file back instead of a larger one.

Private by design

Runs entirely in your browser; your PDFs never leave your device.

How to use PDF Compressor

1
Add your PDFs
Drag and drop one or more PDF files, or click to browse. Owner-locked statements are unlocked automatically.
2
Pick a level
Choose Low, Recommended or Extreme, or Custom to set DPI, JPEG quality or a target size.
3
Compress
Press Compress and watch the progress bar; each file shows its new size and percentage saved.
4
Preview and download
Preview the result, then download each file or everything as a single ZIP.

Common use cases

Email attachments

Get a scanned contract or statement under a 10 MB or 25 MB email limit.

Online applications

Meet the 2 MB or 5 MB upload caps on visa, job and university portals.

Brochures and reports

Shrink photo-heavy marketing PDFs for faster downloads on your website.

Archiving

Save storage space on years of scanned documents while keeping them readable.

Worked example: A 9 MB scanned statement that had to go under 2 MB

A tenant had to upload a 30-page scanned bank statement to a letting portal with a 2 MB limit. The scanner had saved every page as a large JPEG. With Recommended the images were downsampled to 150 DPI and re-encoded with MozJPEG, and the file dropped well under the limit while the printed figures stayed easy to read.

They opened the result in the preview, zoomed in on the account number and totals, then downloaded it. The original stayed untouched on their computer.

Limitations

CMYK, JPEG 2000, JBIG2 and fax-style (CCITT) images are not re-encoded in this version.
Text-only PDFs are usually already compact, so expect small savings.
Downsampling is based on the largest page an image appears on, not its exact on-page size.
Very large files (hundreds of MB) need plenty of memory, especially on phones.

When not to use PDF Compressor

Don't compress a digitally signed PDF you still need to validate; any rewrite breaks the signature.
For print-shop artwork, keep the original high-resolution file.
Avoid Max (rasterise) for documents someone needs to search or copy text from.

Features at a glance

Low, Recommended, Extreme and Custom levels
Target DPI and JPEG quality controls
MozJPEG WebAssembly encoder, self-hosted
Duplicate, unused-object and metadata cleanup
Keeps text and vector graphics selectable
Batch compression with ZIP download
Never outputs a file larger than the original
Optional Max (rasterise) mode for stubborn files

Frequently asked questions

Are my PDFs uploaded to compress them?

No. The PDF Compressor runs entirely in your browser using a Web Worker, pdf-lib and a MozJPEG encoder compiled to WebAssembly. Your files never leave your device, so it is safe for bank statements, contracts and other private documents.

Which compression level should I choose?

Recommended (150 DPI, JPEG quality 72) suits most documents and stays sharp on screen and for normal printing. Low keeps images at 200 DPI for the best quality. Extreme (96 DPI, quality 50) gives the smallest file that still keeps real text. Custom lets you set DPI, quality or a target size.

Will my text still be selectable after compression?

Yes for Low, Recommended, Extreme and Custom. Only images are re-encoded; text, fonts and vector graphics are kept as they are, so you can still select, search and copy text. Only the optional Max (rasterise) mode turns pages into images.

Why did my PDF barely get smaller?

PDFs that are mostly text and vector graphics are usually already compact, and some images (CMYK, JPEG 2000, fax-style black-and-white scans) are left untouched in this version to avoid colour shifts. If the result would be larger than your original, the tool keeps the original file instead.

Can I compress password-protected PDFs?

PDFs that only have an owner (permissions) password, as many bank statements do, are opened and compressed, and the copy you download is no longer restricted. Files that need a password just to open them can't be processed.

Can I compress several PDFs at once?

Yes. Drop in as many PDFs as you like, compress them in one go, see the before and after size and percentage saved for each, preview the result, and download files one by one or all together as a ZIP.

Your privacy matters

PDF Compressor is designed to run in your web browser. File and text tools process bytes in memory on your device rather than uploading them to a ToolsGuru converter API. Network requests you still see are the page itself, analytics, and ads — not a copy of your document sitting in our logs. How we process files, and how to check.