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

Windows does not include a built-in PDF optimizer. Microsoft Edge can open and print PDFs, but it does not provide genuine image optimization or selectable compression levels.

Microsoft Print to PDF recreates the document instead of reliably compressing its existing PDF structure. The new file may be smaller, unchanged, or even larger. Printing can also remove bookmarks, links, forms, comments, layers, accessibility information, and digital signatures.
On Windows 11 or Windows 10, you can reduce PDF size for email with an online PDF compressor or a desktop application. 

• Free Online Tools (No Installation)

Compress a PDF online for free with PDFgear

PDFgear Online is a dedicated free PDF compressor for users who want to compress PDF on Windows without signing up. It offers Low, Medium, and Strong compression levels.

1. Open the PDFgear official website.
2. From the top menu, select PDF Online Tools > Compress PDF.
3. Click Select PDF File and choose the PDF you want to compress.
4. Select Low, Medium, or Strong, then click Compress.
5. Click Download to save the compressed PDF locally.

Start with Low compression when clarity matters and you want to reduce PDF size without losing quality as far as possible. Move to Medium or Strong only if the PDF is still too large for your email provider.

Most PDF compressors provide preset compression levels rather than a specific target size. PDFgear Online also includes a Compress PDF to 100KB tool that targets a 100 KB output, making it useful for websites with a strict 100 KB file-size limit. Select PDF Online Tools > Compress PDF to 100KB, click Select PDF File, and choose the PDF to start the compression.

Use Adobe Acrobat Online PDF Compressor

Adobe Acrobat Online is another browser-based option. It provides High, Medium, and Low compression settings, although the available workflow or download may require an Adobe account.

1. Open the Adobe Acrobat Online Compress PDF tool.
2. Click Select a file and choose the PDF.
3. Select High, Medium, or Low compression.
4. Start the compression and sign in if prompted.
5. Download the smaller PDF and inspect important pages.

Adobe handles online files on its servers. Most free online PDF compressors process only one file at a time, making them suitable for occasionally compressing a small number of PDFs. To compress multiple PDFs in one batch, use a free desktop application instead.

• Desktop applications (Offline Use)

Reduce PDF size without uploading with PDFgear Desktop

PDFgear is a free application for compressing one PDF or multiple PDF files locally. It is useful for private documents, large PDFs, or several files that need to be compressed together.

1. Open the PDFgear desktop app.
2. Select Compress PDF from the main screen.
3. Click Add Files and select one or more PDFs.
4. Select Low, Medium, or High compression.
5. Choose an output folder and click Compress to start the compression.

PDFgear does not require an account or sign-in, making it a practical choice when you need to compress PDF without Acrobat. Because all PDFgear Desktop features run locally and can be used offline, PDFs do not need to be uploaded to a server, helping protect file privacy and security.

PDFgear performs true PDF compression rather than printing each page into a replacement document. It can retain the original PDF structure and supported document elements while optimizing images and redundant data.

Use Adobe Acrobat Pro for advanced optimization

Adobe Acrobat Pro is the paid option when you need detailed control over image resolution, compression, fonts, and removable document data.

1. Open the PDF in Adobe Acrobat Pro.
2. Select All tools > Compress a PDF.
3. Open Advanced Optimization if you need detailed controls.
4. Adjust image downsampling and other settings carefully.
5. Save the optimized PDF under a new name.

Adobe Acrobat Pro cannot guarantee an exact final size. The free Adobe Acrobat Reader can open and email PDFs, but it does not include the complete PDF Optimizer controls available in the paid desktop application.

Use PDFgear Online for quick, free compression without installing software, or Adobe Acrobat Online for occasionally compressing a small number of ordinary files. Choose PDFgear Desktop when you need to batch compress PDF files offline, or compress multiple PDFs at once. Use Acrobat Pro when you need detailed control over image resolution, fonts, and removable document data.

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:

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.

Windows does not include a dedicated PDF compression feature, but there are a couple of practical options.

For a quick built-in workaround, try opening the PDF and printing it again using Microsoft Print to PDF. This may reduce the size of some PDFs, particularly those containing high-resolution images or unnecessary embedded data. However, it can remove bookmarks, form fields, hyperlinks, comments, layers, or digital signatures.

Steps:

1. Open the PDF in Microsoft Edge, Adobe Reader, or another PDF viewer.
2. Press Ctrl + P.
3. Under Printer, select Microsoft Print to PDF.
4. Check the page size, orientation, and page range.
5. Click Print.
6. Choose a folder, enter a new filename, and click Save.
7. Compare the new file size with the original before emailing it.

For better control, a dedicated PDF application is usually more reliable:

• PDFgear is a good free option for everyday use. It can compress PDFs offline and is straightforward if you mainly want to reduce file size before emailing.
• Adobe Acrobat Pro offers more advanced optimization controls, including image downsampling, removing unnecessary objects, and batch processing multiple PDFs. It is better suited to professional workflows, but it requires a paid subscription.

For scanned or image-heavy PDFs, most of the size reduction usually comes from lowering the image resolution. Around 150 to 200 DPI is often a reasonable balance for screen viewing while keeping text readable.

Save the compressed PDF as a new file and check the text, images, links, and forms before sending it, especially if the document contains signatures or interactive elements.

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.