PPing Apps Lab
Guides·ResizePing

Compress PDF to 100 KB on Android and iPhone: Reduce PDF Size to 100 KB

Need to reduce a PDF to 100 KB? On Android, ResizePing Pro lets you type 100 KB. Free, pick Smallest and check the estimate before you save.

Published October 23, 2026 · Last updated October 27, 2026

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ResizePing Compress Complete screen showing a sample PDF before and after size

To compress a PDF to 100 KB on Android, open it in ResizePing and type the size you want. The exact-size target is a Pro feature. Without Pro, choose the Smallest level, read the estimated size and compress. On iPhone, ResizePing compresses with the same three levels.

Need a smaller PDF? ResizePing compresses PDFs on your phone. Get it on Google Play or the App Store.

Steps

The screenshot is from Android.

  1. Install ResizePing, tap Select PDF, and pick the PDF.
  2. In What do you want to do?, choose Compress PDF.
  3. Android with Pro: choose Custom size, enter 100 and pick KB.
  4. Free, Android or iPhone: under Compression level, pick Smallest. Balanced and Best quality keep more detail and give bigger files.
  5. Check Estimated output before you save.
  6. Tap Compress. The Compress Complete screen shows the size before and after.

If it won't go that small

A 100 KB PDF is very small, so a scanned PDF of full-page photos may not reach it. If the size you typed is lower than the PDF can reach, ResizePing says so and shows the smallest size it can get.

  • Split the PDF so you keep only the pages the form needs, then compress again.
  • Re-scan at a lower resolution, then compress the new file.

What to know

  • Never uploaded to our servers.
  • The sizes in the screenshot are for a sample file. Results depend on what is inside your PDF.

FAQ

  • How do I compress a PDF to 100 KB? On Android, open the PDF in ResizePing, choose Compress PDF, pick Custom size, enter 100 and choose KB. That target is a Pro feature. Free, use the compression levels and check the estimated size.
  • How do I reduce PDF size to 100 KB? Open the PDF in ResizePing, choose Compress PDF and pick Smallest, then read the estimate. With Pro on Android, use Custom size and enter 100 in KB.
  • Will the PDF definitely be under 100 KB? Not always. Check the estimate before saving.
  • Can I type a target size on iPhone? On iPhone, compress with the Smallest, Balanced or Best quality levels and check the estimate.
  • Is the custom size free? No, it is a Pro feature. The compression levels are free.
  • Does it upload my PDF? No. Never uploaded to our servers.

On a computer

On a computer instead? Ping Tools Lab has a browser version: Compress PDF to 100 KB.