Privacy-first

Compress PDF privately

This page is for people who need a smaller PDF without handing the file to a random upload service. PDFWhisk processes supported files locally in the browser and gives you clear before/after size feedback.

At a glance

Use this page to compress files quickly with a guided workflow.
Accepted input: .pdf.
Output: downloadable files generated in-browser for supported workflows.

2MB preset 10MB preset

Local processing No server file storage Mobile-friendly

Upload Choose your file
Process Runs locally
Download Save result

Drop your files here

or tap to browse · accepts .pdf

Runs in your browser. No file uploads for supported tools.

Best on desktop for 100MB+ files · mobile recommended under ~100MB.

Runs locally No file uploads No server storage

How local processing works

Your PDF is processed in your browser using local JavaScript libraries.
PDFWhisk does not upload your file to a processing server for supported tools.
Only normal page assets load from the site (HTML/CSS/JS), not your document contents.

Read the privacy proof

Support: contact form (reply in ~24h)

Security & privacy details

How this tool helps

Reduce the file size of your PDF documents instantly, right in your browser. Our PDF compressor uses smart optimization to shrink files by up to 90% while preserving text clarity, image quality, and formatting. Perfect for email attachments, uploading to portals, or saving storage space. Unlike other tools, your PDF never leaves your device - all compression happens locally using your browser's processing power. Choose from three quality levels: high compression for maximum size reduction, balanced for the best mix of quality and size, or low compression to keep near-original quality. Works with scanned documents, reports, presentations, and any PDF file. Use it when you need to split large PDFs for portal limits, compress PDFs on iPhone, reduce email attachment size.

Best for

Email attachments Job portals Scanned documents iPhone/Android uploads

How it works

1

Open PDFWhisk Compress tool

Visit PDFWhisk in your browser and open the Compress PDF tool. No account or app needed — it runs entirely in your browser.
2

Add your PDF

Drag your PDF file onto the page, or click to browse and select it from your device. Your file is not uploaded to any server.
3

Choose compression level

Select Light (keeps quality high) or Heavy (reduces file size most). For most upload portals, Medium works well.
4

Compress the PDF

Click Compress and wait a few seconds while your browser processes the file locally.
5

Download the result

Click Download to save your compressed PDF. The original file is unchanged.

More files today? Free covers 3 tasks a day and files up to 50MB. For unlimited tasks and bigger files, Pro passes start at £1 for 24 hours. One-off payment, no subscription, and your files still stay on your device.

Intent guide

Compressing privately matters most for the documents people most often need to shrink: bank statements, payslips, ID scans and signed contracts.

What 'private' means here

Many online compressors upload your PDF to their server, process it there and promise to delete it after an hour or two. PDFWhisk's compressor runs in your browser tab instead: the page and its scripts download to your device, and the PDF is read and rewritten in memory on your device. There is no copy on a server to delete.

How to check for yourself that nothing is uploaded

On a laptop, open your browser's developer tools (F12, or Cmd+Option+I on a Mac), choose the Network tab, then run the tool. You will see the page's own scripts load and, on the free tier, one small request to /api/pw-quota with an empty body (it counts free tasks per day). No request carries your PDF: compare the request sizes with the size of your file. The processing itself is done by pdf-lib and pdf.js running in the tab.

What the compressor actually changes

Most of a large PDF's weight is images: scanned pages and photos. The compressor re-encodes those images at a lower resolution and quality until the file fits the target you choose, and leaves text as text, so typed words stay sharp. A PDF that is already mostly text may only shrink a little; splitting it or removing pages is then the better route.

A sensible order of work for sensitive files

Remove pages you do not need to send first (Delete Pages), then compress to the recipient's limit, then open the result and zoom in on account numbers, dates and signatures. Keep your original: compression is one way, and you may need the full-quality version later.

Before you upload/share

Open the PDF and check every page before you send or upload it.
Keep the original files until the recipient or portal has accepted the document.

Frequently asked questions

Does PDFWhisk upload my file to a server?

Supported tools process the document locally in your browser. The site loads page assets, but the PDF content is not uploaded for processing.

Is this suitable for bank statements or contracts?

Yes, if you prefer local processing for sensitive documents. Still review the output before sharing and keep the original file.

Can I choose a target size?

Yes. Use the presets (2MB, 5MB, 10MB, 25MB) or a custom target size.

What if the PDF will not shrink much?

Text-only PDFs may already be efficient. In that case split or remove pages rather than forcing aggressive compression.

What to do next

Chain tools together for a complete workflow.

Merge PDF

Combine multiple PDF files into one document

Split PDF

Extract pages or split a PDF into multiple files

PDF to JPG

Convert PDF pages to high-quality JPG images