How to compress a pdf file to reduce the size before emailing on Windows?

Ask the built-in AI tool Copilot to compress a PDF file on Windows 11 and Windows 10.

Ghost script is an excellent, completely free choice to compress PDF file size, especially for your file sizes ranging from 50 MB to 100 MB. It is a professional-grade tool that has been the industry standard for PDF and PostScript processing for decades.

How to Compress PDF file size using Ghost script

First, you need to install Ghost script, which is a command-line tool capable of processing PDF files efficiently. Once installed, you can run a specific command to compress your large PDFs.

1. Download and install Ghost script.

2. Open Command Prompt:

• Press Windows + R, type cmd, and press Enter to open the command line interface.

3. Run the compression command:

• Navigate to the folder containing your PDF files, or specify the full path in the command.
• Use the following command to compress your PDF:

bash

gswin64c -sDEVICE= pdfwrite -dCompatibilityLevel= 1.4 -dPDFSETTINGS=/ ebook -dNOPAUSE -dQUIET -dBATCH -sOutputFile=compressed,pdf input,pdf

Here is a breakdown of what these options mean:

• gswin64c: Calls the Ghost script executable on Windows.
• -sDEVICE=pdfwrite: Tells Ghost script to output a PDF file.
• -dPDFSETTINGS: This is the most important setting for controlling the file size. The table below explains the four main presets.
• -sOutputFile= compressed, pdf: Specifies the name of your new, compressed file.
• input.pdf: The name of your original, large file.

For those comfortable with command-line tools, pdfsizeopt is a specialized, cross-platform program specifically designed to convert large PDF files into small ones.

Key features:

• Cross-platform — Works on Windows, Linux, and macOS
• Focus on optimization — Developed specifically for reducing PDF file sizes
• Collection of best practices — Uses proven optimization techniques

How to Compress a PDF Using pdfsizeopt (Step by Step)

Step 1: Obtain pdfsizeopt

Step 2: Open a Command Prompt

• You'll need to use the Command Prompt (cmd) or PowerShell since pdfsizeopt is a command-line application. Navigate to the folder containing your PDF file, or ensure pdfsizeopt is in your PATH.

Step 3: Run the Basic Compression Command

• The simplest way to learn how to compress a PDF with pdfsizeopt is to use the basic command structure:

bash

pdfsizeopt input,pdf output.pdf

• For example, if you have a file called thesis.pdf that you want to compress to thesis_optimized.pdf, you would run:

bash

pdfsizeopt thesis,pdf thesis _ optimized,pdf

Step 4: Use Advanced Options for Maximum Compression

Step 5: Batch Process Multiple PDFs

Here is where things get interesting for anyone trying to compress PDF file size. When you print an existing PDF to the Microsoft Print to PDF printer, Windows re-renders the entire document from scratch. During this re-rendering process, it applies its own default compression settings to images, fonts, and other elements inside the file. This often results in a smaller output than the original, especially if the original PDF contained high-resolution images or heavy metadata that Windows strips away.

Step-by-Step

1. Open your PDF file using any application that can display it.

2. Press Ctrl + P on your keyboard to open the Print dialog box. This is the same shortcut you would use to print a physical document.

3. Look at the Printer selection dropdown near the top of the dialog box. Click it and select "Microsoft Print to PDF" from the list of available printers.

4. Adjust any settings you want to change. Under "More Settings" or similar options, you can sometimes lower the page scaling or choose different paper sizes. Printing at a smaller scale can help further compress PDF file size because the resulting pages contain less visual information. However, leaving settings at their defaults usually works fine.

5. Click the Print button. Windows will ask you where to save the new PDF file. Choose a location, give it a name, and click Save.

6. Compare the file sizes. Navigate to both the original PDF and the new one, right-click each, and select Properties. Look at the "Size" field. You will likely see that the new version is smaller.

How to compress a PDF? If you have Microsoft Word installed (which many Windows PCs do), this is the cleanest offline method. It works best if your PDF was originally created from a document, but Word can open most PDF files directly.

How to compress a PDF:

1. Open Word 

2. Go to File > Open and select your PDF file

3. Word will display a message saying it will convert the PDF to an editable document. Click OK

4. After the document opens, go to File > Save As and choose PDF as the format

5. Before saving, click the Options button

6. In the dialog box, select "Minimum size (publishing online)" instead of "Standard"

7. Click OK, then Save

Why this works: Word automatically optimizes images for screen viewing rather than high-quality printing. This can dramatically reduce file size—sometimes from 15MB down to 1-2MB for text-heavy documents.

Bluebeam PDF.

If your PDF file is too large for email, cloud upload, or sharing, the built-in "Reduce File Size" feature in Bluebeam Revu is one of the fastest ways to compress a PDF file on Windows. This method automatically removes unnecessary data and optimizes images without requiring advanced settings, making it a good option for construction drawings, reports, and scanned documents.

How to reduce PDF size before emailing

1. Open the PDF file in Bluebeam Revu.
2. Click Document from the top menu.
3. Select Reduce File Size.
4. Choose the desired compatibility version.
5. Click OK to begin compression.
6. Save the new PDF file with a different name.

In summary, Bluebeam's Reduce File Size tool is a quick and beginner-friendly way to compress large PDFs while keeping the document readable. It works especially well for everyday sharing and can noticeably reduce oversized PDFs created by scanners, CAD software, or other PDF editors.

Try to open the PDF file from chrome browser, and print-to-pdf through the browser instead of adobe. The file size should be a lot more reasonable from my experience. 

That actually works surprisingly well for compressing PDFs files, especially ones bloated with embedded metadata, editing history, forms, annotations, or unnecessarily high-quality assets.

How to compress PDF file size on Windows 11/10 before emailing:

1. Open the PDF in Google Chrome.

2. Press Ctrl + P.

3. Set the printer to Save as PDF or Microsoft Print to PDF.

4. In “More settings,” lower the scale or simplify options if needed.

5. Click Save and create a new PDF.

This basically re-renders the document into a cleaner PDF and often strips out extra junk that Adobe preserves. In many cases, the output file becomes much smaller without noticeably hurting readability.

A few things to know though before reducing PDF file size:

• Interactive forms, bookmarks, hyperlinks, layers, or signatures may be removed.
• Searchable text usually stays intact if the original PDF already contained text.
• Scanned PDFs with huge images can still remain large, but often shrink a lot anyway.
• “Print to PDF” is sometimes faster and more effective than Acrobat’s default compression for everyday sharing.

If the PDF is mainly for viewing, emailing, uploading, or archiving, this trick is often one of the easiest solutions.

You can usually reduce a PDF’s size by opening it in Adobe Acrobat and using the “Compress PDF” or “Reduce File Size” option. If you don’t have Acrobat, there are also free PDF compression tools available online that work well for basic files. Another thing that helps is lowering image quality inside the PDF before saving it again, especially if the document contains screenshots or scanned pages.

Adobe Acrobat Pro, one of the best PDF tools available on Windows.

To compress a PDF file with Adobe Acrobat on Windows, open the PDF in Acrobat first. Then go to Menu > Save as Other > Reduced Size PDF. In the compatibility window, choose the Acrobat version you want the file to support, click OK, choose a save location, rename the file if needed, and click Save. This is the fastest way to reduce PDF size in Acrobat.

For more control to reduce the size of a PDF file, use Menu > Save as Other > Optimized PDF. In the PDF Optimizer window, choose Standard from the settings menu, then adjust options such as image downsampling, image compression, font embedding, transparency, hidden data, comments, bookmarks, and unused objects. Adobe notes that the Images, Fonts, Transparency, Discard Objects, Discard User Data, and Clean Up panels can all help reduce file size.

For scanned PDFs or image-heavy PDFs, Optimized PDF usually gives better results because most of the file size comes from large images. You can lower image resolution, use JPEG compression, and remove unnecessary metadata or embedded objects. Just avoid setting image quality too low if the PDF contains text screenshots, product manuals, invoices, or anything that must stay readable. Adobe’s PDF Optimizer is designed to balance file size and document quality through image, font, and object settings.