Short answer: To reduce PDF file size on a phone, open arcanizepdf.com/tools/compress in your browser, select the PDF, choose a compression level and tap Compress PDF. The file is compressed on your device and is not uploaded. On Android you can also do it offline with the Arcanize app.
How to compress a PDF on Android or iPhone in the browser
This works in Chrome, Safari and other mobile browsers, and on a computer.
- Open arcanizepdf.com/tools/compress.
- Tap Select File and choose the PDF.
- Pick a compression level: Extreme, Recommended or High Quality.
- Tap Compress PDF and wait for it to finish.
- Tap Download File to save the smaller PDF.
The first run takes longer because the browser downloads the compression engine. After that, the work happens on your phone. There is no sign-up and no watermark.
Which compression level should you choose?
| Level | What it does | Use it when |
|---|---|---|
| Extreme | Lowers images to roughly screen resolution for the smallest file | A form has a strict limit such as 1 MB or 2 MB |
| Recommended | Keeps images clear enough to read comfortably on a screen | Emailing or sharing a scanned document |
| High Quality | Keeps images sharp enough to print, so the file stays larger | The PDF will be printed |
Typed text stays sharp at every level because it is stored as text, not as a picture. Scanned pages are pictures, so Extreme can soften them. If a scan has to stay easy to read, use Recommended.
How to compress a PDF with the Arcanize Android app
The Arcanize app compresses PDFs on your phone without an internet connection.
- Install Arcanize from Google Play.
- Open Compress PDF.
- Select the file.
- Tap Compress.
- Save the smaller version.
The app is free and does not add a watermark.
How much smaller will the PDF get?
It depends on what is inside the file.
| Type of PDF | Typical reduction |
|---|---|
| Scanned documents and photos | Large. These are made of images, which shrink the most |
| Mixed text and images | Moderate |
| Text-only PDFs, such as Word exports | Small. They are already lean |
You cannot set an exact target such as 100 KB or 200 KB. Start with Extreme, check the size, and move to Recommended if the result is hard to read. A few pages of text can drop under 100 KB. A long scanned document may not get that small without becoming unreadable.
If the PDF is still too large
- Split it. Use Split PDF to keep only the pages the form asks for.
- Rescan at a lower quality. A scan made at very high resolution starts large. Scanning in black and white also helps.
- Remove extra pages. Covers, blank pages and duplicates add size for no benefit.
Frequently Asked Questions
How do I reduce PDF file size on my phone for free?
Open the Arcanize Compress PDF tool in your phone's browser, select the file, choose a level and tap Compress PDF. It is free, with no sign-up and no watermark.
Will compressing a PDF make the text blurry?
Typed text stays sharp. Scanned pages are images, so the Extreme level can soften them. Use Recommended when a scan needs to stay clear.
How do I compress a PDF to 100 KB or 200 KB?
Use the Extreme level and check the result. Whether the file reaches 100 KB or 200 KB depends on its content: short text documents usually can, long scans often cannot without losing readability.
Is my PDF uploaded when I compress it?
No. The Arcanize web tool compresses the file in your browser, and the Android app works offline. The file stays on your device.
Can I compress a password-protected PDF?
Unlock it first with the Unlock PDF tool, using its password, then compress the unlocked copy.