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Quick answer
To reduce a PDF's file size, open Zappy Compress PDF, add your file, choose Light (about 20% smaller), Moderate (60–70% smaller) or Extreme (80–90% smaller) and click Compress PDF. The smaller file downloads straight away. Text stays sharp, because compression only shrinks the images inside the PDF.
How to reduce PDF file size in 3 steps
Add your PDF
Open Compress PDF and drop in a PDF up to 200 MB. Scanned documents work too.
Pick a level
Light keeps quality for printing, Moderate is small enough to email, and Extreme gives the smallest file for strict upload limits.
Compress and download
Click Compress PDF. The original and new sizes are shown, and the smaller PDF downloads.
Why some PDFs are so big
Text takes up very little space in a PDF. The weight almost always comes from images: photos, scanned pages and high-resolution graphics. A 20-page scan can easily be 20 MB, while a 20-page text report is often under 1 MB.
That is why compression works so well on scans and image-heavy files, and why text stays crisp: words are not pictures, so they are never blurred.
Which compression level to choose
Swipe to compare →
| Level | Typical result | Best for |
|---|---|---|
| Light | About 20% smaller | Printing and keeping photos at full quality |
| Moderate | 60–70% smaller | Email attachments and sharing: the usual choice |
| Extreme | 80–90% smaller | Strict upload limits on forms and portals |
How to make a PDF small enough to email
Gmail allows attachments up to 25 MB and Outlook up to 20 MB. Anything bigger is turned into a cloud link or bounced. Moderate compression gets most documents well under those limits, and it keeps them easy to download on a phone.
How to reduce PDF file size on a Mac
Preview has a built-in option: open the PDF, choose File > Export, and set Quartz Filter to Reduce File Size. It often shrinks files a lot, but it can make scanned pages noticeably blurry because you can't choose how strong it is. Compress PDF gives you three levels to pick from.
How to reduce PDF file size on Windows and iPhone
Windows has no built-in PDF compressor, and reducing file size in Adobe Acrobat needs a paid subscription. On Windows, a Chromebook or an iPhone, the simplest free option is to open Compress PDF in your browser.
More ways to shrink a PDF
- Scan at 150–200 DPI instead of 600 DPI. It is plenty for documents and makes the file much smaller from the start.
- Scan in grayscale when color doesn't matter.
- Export from the source (Word, Excel, Google Docs) instead of scanning a printout.
- Remove extra pages such as blank backs of scanned sheets.
Frequently asked questions
How do I reduce a PDF file size for free?
Open Zappy Compress PDF, add your file, choose Light, Moderate or Extreme and click Compress PDF. The smaller file downloads with no account or watermark.
Will compressing a PDF reduce the quality?
Text stays sharp at every level. Photos and scans lose a little detail at Moderate and more at Extreme, which is where the savings come from.
How much smaller will my PDF get?
About 20 percent on Light, 60 to 70 percent on Moderate, and 80 to 90 percent on Extreme. Scans and image-heavy PDFs shrink the most.
How do I reduce PDF file size on a Mac?
In Preview, choose File, Export, and set Quartz Filter to Reduce File Size. For more control over quality, use Compress PDF in your browser.
How do I make a PDF small enough to email?
Use the Moderate level. It usually brings documents well under Gmail's 25 MB and Outlook's 20 MB limits.
Why is my PDF still large after compressing?
It is probably mostly images or scanned pages. Try Extreme, remove unneeded pages, or split it into smaller files.
What happens to my file?
It is compressed on our server and deleted automatically afterwards. It is never shared.