How to Reduce PDF Size for Email Attachments

A complete guide to shrinking large PDF files to under 100kb or 25MB for Gmail, Outlook, and government portals without losing quality.

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We've all been there: You're trying to send an important document via Gmail or Outlook, but you get the dreaded error message: "Attachment size exceeds the allowable limit". Most email providers cap attachments at 25MB. But what if your file is 50MB?

Instead of splitting the file or trying to take screenshots, the professional solution is to use a PDF Compressor. In this guide, we'll explain how to reduce PDF size securely and why our offline tool is the best choice for sensitive documents.

Why are PDF files so large?

PDFs often contain high-resolution images, embedded fonts, and hidden metadata that you don't actually need for a standard email attachment.

Step-by-Step: How to Reduce PDF Size to 100kb

If you are applying for a government job or college admission, you often need to reduce your file size to exactly 100kb or 200kb. Here is how to do it using The PDF Mechanic:

  1. Open the Compressor Tool: Navigate to our Compress PDF page.
  2. Select Your File: Click "Choose File" to select the document from your mobile or computer.
  3. Adjust Settings: Our smart algorithm will automatically calculate the best ratio between quality and size.
  4. Download: Once processed (which takes milliseconds), download your optimized file.

Why use "Client-Side" Compression?

Most online PDF tools ask you to upload your file to their server. This is risky if you are handling bank statements, Aadhaar cards, or business contracts.

"Client-side means the compression happens right on your device (browser). The file never travels over the internet."

The PDF Mechanic is unique because it works 100% offline. Once the page loads, you can even turn off your WiFi, and the tool will still work. This ensures maximum privacy and speed.

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Frequently Asked Questions

How can I compress a PDF to 200kb online?
Simply upload your file to our PDF Compressor. The tool automatically removes redundant data. If the file is still too big, try converting it to images and back to PDF, or check if you have unnecessary high-resolution images in the document.
Does this work on Mobile (Android/iPhone)?
Yes! The PDF Mechanic is a Progressive Web App (PWA). It works perfectly on Android Chrome and iOS Safari. Since it works offline, it saves your mobile data too.
Is there a daily limit?
No. Because we don't use servers to process your files, there are no costs for us. You can compress unlimited files for free, forever.
How do I check my PDF size?
On Windows, right-click the file and select 'Properties'. On Mac, press Command+I. If it's over 25MB (25,000 KB), you need to compress it for email.
Will my text become blurry?
Usually, no. Text in PDFs is vector-based, which scales perfectly. Compression mostly affects images. If your PDF is a "scanned" image, there might be slight quality reduction, but text documents remain sharp.