PDF Compressor
Reduce your PDF file size instantly in your browser – no uploads, no server, 100% private.
Drag & drop your PDF here
Max 25 MB · Processed locally, never uploaded
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Compression Level
What does this PDF Compressor do?
This tool shrinks the file size of a PDF directly inside your browser. Pick a compression level, and it re-renders every page at a reduced quality, then rebuilds the file as a smaller PDF you can download right away. There’s no upload to a server involved at any point, so your document never leaves your device.
It’s built for the everyday moment when a PDF is simply too big: an email that won’t send, a form upload that gets rejected, or a scanned document eating up storage space. Pick a level, run the compression, and download a lighter version in seconds.
If you end up with several compressed files that belong together, our Merge PDF tool can combine them into a single document afterward.
How to Use This PDF Compressor?
- Upload your PDF. Drag and drop a file onto the upload zone, or click Choose PDF to browse for one. Files up to 25 MB are supported.
- Pick a compression level. Choose Low, Medium, or High depending on whether you want to keep more visual quality or shrink the file as much as possible.
- Click Compress PDF. The tool processes your document page by page, right there in your browser.
- Watch the progress bar. A live progress indicator shows which page is currently being processed, so you always know how far along the compression is.
- Check the results. Once it’s done, you’ll see the original size, the new compressed size, and the percentage saved.
- Download the compressed file. Click Download to save the smaller PDF to your device, ready to email, upload, or share.
Built-In Features
100% Browser-Based
Compression happens entirely on your device. Your PDF is never uploaded to a server, so sensitive documents stay private.
Three Compression Levels
Choose Low, Medium, or High compression to balance visual quality against how small the final file needs to be.
Live Progress Tracking
A progress bar reports each page as it’s processed, so you can see exactly how compression is moving along on longer files.
Before & After Comparison
Once compression finishes, you’ll see the original size, the compressed size, and the exact percentage saved side by side.
Helpful Error Messages
If a file is password-protected, corrupted, not a valid PDF, or over the 25 MB limit, the tool tells you exactly what went wrong.
One-Click Download
Download the compressed file with a name that’s clearly marked, so it’s easy to tell apart from your original.
How PDF Compression Works
Rather than just stripping out metadata, this tool reduces file size by rebuilding your document from lighter, recompressed page images. Here’s what actually happens once you click Compress PDF.
Each Page Is Rendered
Every page of your PDF is drawn onto a canvas inside your browser, the same way it would look if you opened it to read.
Each Page Is Recompressed
That rendered page is saved again at a lower resolution and quality, set by the compression level you picked. Higher compression trims more detail to save more space.
A New PDF Is Assembled
The recompressed pages are placed into a brand-new PDF, keeping each page at its original dimensions so it still looks and prints the right size.
A Note on Text and Scanned Documents
This tool compresses a PDF by converting each page into a re-optimised image and rebuilding the file from those images. That approach works especially well on scanned documents and image-heavy files, since it directly targets the part of the file that’s actually taking up space.
It’s worth knowing, though, that once a page has been turned into an image, any text on that page is no longer selectable, searchable, or copyable in the compressed file, even if it was in the original. If you need to keep text searchable, it’s worth checking the compressed file before replacing your original, or sticking with a lighter Low setting to preserve more detail.
Choosing the Right Compression Level
All three levels are available directly in the tool. Here’s a general guide to when each one tends to fit best.
| Level | Typical Reduction | Best For |
|---|---|---|
| Low | ~10–25% | Documents where visual quality matters most, like designs or detailed scans |
| Medium | ~25–55% | General everyday sharing, such as email attachments and reports |
| High | ~55–80% | Large scanned archives or files headed for size-limited web uploads |
Why PDF File Size Matters
Email Attachments
Most inboxes cap attachment size, and an oversized PDF can bounce back undelivered instead of reaching the recipient.
Website & Form Uploads
Job portals, application forms, and government sites often set strict upload limits, sometimes just a few megabytes.
Faster Sharing
Smaller files upload and download faster, which matters most on mobile data or slower connections.
Cloud Storage Limits
Free storage tiers fill up quickly once you’re saving scanned paperwork and reports over months or years.
Messaging Apps
Some chat and messaging platforms automatically compress or reject files over a certain size, sometimes reducing quality further than you’d choose yourself.
Long-Term Archiving
Storing scanned records for years adds up. Smaller files mean lower backup costs and quicker restores.
Typical File Size Limits by Use Case
These are general reference points, not guarantees. Limits vary by provider and change over time, so always confirm the current limit for the specific service you’re using.
| Use Case | Typical Limit |
|---|---|
| Gmail attachment | Around 25 MB |
| Outlook attachment | Around 20–34 MB |
| WhatsApp document share | Around 100 MB |
| Typical job or form portal upload | Around 5–10 MB |
| Typical WordPress media upload | Around 2–8 MB, depending on hosting |
Why Different Compressors Give Different Results
Run the same PDF through two different compressors and you’ll often get two different file sizes. That’s expected, and it comes down to methodology rather than one tool being “better” in every case.
Some compressors focus on stripping metadata and embedded fonts while leaving images untouched. Others, like this one, recompress the visual content of each page. The resolution and quality settings behind each compression level also vary from tool to tool, which is why a “Medium” setting in one app can produce a very different result from “Medium” in another.
The type of PDF matters too. A scanned document made up mostly of images tends to shrink a lot more than a text-heavy PDF exported from a word processor, since there’s simply more image data to compress in the first place.
Tips for Getting the Best Results
Start With Medium
Medium gives a reasonable balance of size and quality for most everyday documents. Adjust up or down from there once you see the result.
Match the Level to the Content
Photo-heavy or scanned pages tolerate higher compression well. Documents with fine print or detailed diagrams do better on Low.
Combine Files Afterward
Compressing several documents separately? Our Merge PDF tool can join them into one file once each has been shrunk.
Split Long Documents First
For a very long file, breaking it into sections with Split PDF can make it easier to share only the pages someone actually needs.
Just Need the Images?
If you only need a few pages as pictures rather than a full PDF, our PDF to JPG Converter extracts them directly.
Review Before You Send
Open the compressed file and check that it still reads clearly, especially for documents with small text or fine detail.
Frequently Asked Questions
How does this PDF compressor work?
It renders each page of your PDF, recompresses it as an optimised image based on the level you choose, and rebuilds a new, smaller PDF from those pages.
Is this PDF compressor free?
Yes. The tool is free to use with no sign-up required.
Is my PDF uploaded anywhere?
No. Compression runs entirely in your browser. Your file is never sent to a server.
What’s the maximum file size I can compress?
Files up to 25 MB are supported. Larger files will show an error asking you to choose a smaller one.
Which compression level should I choose?
Low keeps the most visual quality, Medium offers a balanced everyday option, and High produces the smallest file at the cost of more visible quality loss.
Will compressing reduce the quality of my PDF?
Yes, to some degree. Compression trades a small amount of visual quality for a smaller file size. Lower compression levels keep more detail than higher ones.
Will I still be able to select or search text after compressing?
No. Because each page is converted into an image during compression, text on that page is no longer selectable, searchable, or copyable in the compressed file.
Can I compress a password-protected PDF?
Not directly. Password-protected or encrypted PDFs need to be unlocked first before they can be compressed.
Why didn’t my file get much smaller?
If a PDF is already lightly formatted or mostly text with few images, there’s less to compress, so the reduction will naturally be smaller than with an image-heavy scan.
Can I compress a PDF with many pages?
Yes. The tool processes a document page by page and shows progress as it works through longer files.
Does this tool work on mobile devices?
Yes. It works in mobile browsers as well as desktop browsers.
Is there a limit to how many times I can use this tool?
No. You can compress as many PDFs as you need, one at a time, at no cost.