Large PDF files can be frustrating when you need to email them, upload them online, or free up storage space. Luckily, you can shrink a PDF by up to 90% using free online tools, built-in system features, or professional software. Whether you're using a computer, mobile device, or web-based service, compression is a quick and simple process. Just upload your file, choose your preferred compression level, and download the optimized version in seconds. In this guide, we’ll walk you through the best methods for reducing PDF size on different devices with step-by-step instructions.

Compress a PDF Online (Works on Any Device)

If you want a fast, hassle-free way to shrink your PDF file, online compressors are your best bet. Here’s how:

• Go to a reliable online PDF compressor like Smallpdf, ILovePDF, or ThePDFFox.

• Click on “Upload” or “Choose File” and select your PDF.

• Pick a compression level:

  1. Basic Compression (Free): Decent file reduction with good quality.
  2. Strong Compression (Premium): Maximizes size reduction but may slightly lower image quality.
  

• Hit “Compress” and wait a few seconds.

• Download your optimized PDF and check the new size.

These online tools work across Windows, Mac, Android, and iOS without needing installations.

Compress a PDF on Windows

If you’re using a Windows PC, you have multiple ways to compress PDFs:

1. Adobe Acrobat Pro (Best Quality Compression)

• Open Adobe Acrobat Pro.

• Click “File” > “Open” and select your PDF.

• Navigate to “File” > “Save As Other” > “Reduced Size PDF”.

• Choose a lower compatibility version for higher compression.

• Click “OK” and Save the smaller file.

2. Free Software (For Users Without Adobe)

• Download ORPALIS PDF Reducer or Free PDF Compressor.

• Install and launch the software.

• Click “Add File” and upload your PDF.

• Choose a compression mode:

  1. Screen (Max Compression) – Best for viewing on screens.
  2. Ebook (Balanced) – Good compression with readable quality.
  3. Printer (Minimal Compression) – Keeps high quality.
  

• Click “Compress” and save the optimized file.

Compress a PDF on Mac

Mac users can shrink PDFs easily using built-in tools or third-party apps.

1. Use Preview (Built-In & Free)

• Open the PDF in Preview.

• Click “File” > “Export”.

• Click the “Quartz Filter” dropdown and select “Reduce File Size”.

• Choose a save location and click “Save”.

2. Use a Mac App (For More Control)

• Download PDF Squeezer or Cisdem PDF Compressor.

• Open the app and drag your PDF inside.

• Select a compression level:

  1. Low Compression – Keeps highest quality.
  2. Medium Compression – Balances quality and size.
  3. High Compression – Maximum file size reduction.
  

• Click “Compress” and save your file.

Compress PDFs on Mobile (Android & iOS)

If you’re using a smartphone or tablet, compressing PDFs is simple with apps or web tools.

1. Online PDF Compression (No Installation Needed)

• Open your browser and visit ILovePDF, Smallpdf, or ThePDFFox.

• Tap “Upload” and select your file.

• Choose a compression level:

  1. Basic Compression: Reduces size while keeping good quality.
  2. High Compression: Maximizes reduction for large files.
  

• Tap “Compress” and wait a few seconds.

• Download your optimized file.

2. Use a Mobile App

• Install Adobe Acrobat Reader or PDF Compressor.

• Open the app and select “Compress PDF”.

• Upload your file and pick a compression level:

  1. High: Maximum reduction, slight quality loss.
  2. Medium: Best balance of size and clarity.
  3. Low: Minimal compression, best for high-quality documents.
  

• Save and share the compressed PDF.

Final Thoughts

Compressing PDFs makes sharing, storing, and uploading documents much easier. Whether you choose online tools, built-in features, or dedicated software, you have plenty of options to reduce file size while keeping quality intact. For quick compression, online tools like ILovePDF, Smallpdf, and ThePDFFox are your best choice. If you need more control, Adobe Acrobat Pro, ORPALIS PDF Reducer, or Preview on Mac offer advanced features. Mobile apps also provide a convenient way to shrink PDFs on the go. Try different methods and find what works best for your needs!