How To Compress PDF to a Chosen Size Online

If you’re looking for a free online tool to quickly compress a PDF and reduce file size, try this:

That should get you the smaller PDF size you need with minimal headache. However, there are other options—both online and native to Mac and Windows—that we’ll show you below.

Large PDF sizes are common, which surprises many people. While PDFs seem like simple static documents, they’re actually made of multiple components. These include embedded fonts and high-resolution images, which are the most common culprits of large PDFs. If you have a file that’s too big to share or upload, that’s likely the reason.

The good news is you don’t need to diagnose the problem to fix it.

Below, we share three—free—ways to compress a PDF file size using:

1. Smallpdf’s online PDF compressor (works on any device)
2. Mac’s Preview feature (for Mac users)
3. Microsoft’s Print to PDF option (for Windows users)

We’ll also share the pros and cons of each option so you can find the one that’s right for you.

How To Reduce PDF Size Online With Smallpdf

If you have an internet connection, the smoothest way to compress a PDF without losing quality is with Smallpdf’s Compress PDF tool. It just takes seconds, and you don’t even need to register or sign up for an account.

Smallpdf offers two options: basic or strong compression. Basic compression is completely free to use. Strong compression is free to trial, but requires a Pro account if you’ll be using it often.

How to reduce PDF file size for free with Smallpdf:

1. Go to the Compress PDF online tool.
2. Drag and drop your PDF into the box.
3. Choose either ‘Basic’ or ‘Strong’ compression.
4. Click “Compress” and wait just a second.
5. Download your PDF.

I tested it with a 235-page, graphic intensive photo book, and in a matter of seconds it reduced my PDF from 223 MB to 44 MB with Basic compression.

When I ran it through Strong compression, it compressed those 223 MB to 29 MB. Pretty impressive.

Key advantages:

• Intuitive, user-friendly interface
• No registration or installation required
• Built-in options to convert and edit PDFs

It’s also completely secure with advanced TLS encryption, and Smallpdf deletes all uploaded files after compression unless you choose to create an account.

The downside is that you need an internet connection, and the Strong compression option is a Pro feature beyond the 7-day free trial. But for most people, the Basic compression is more than enough to make file sizes small enough for sharing and uploading.

If instead you prefer native options over online tools, you have choices already inside your Mac and Windows machines.

How To Make a PDF Smaller on Mac

Your Mac has a built-in PDF compressor, with some strengths and limitations we’ll look at below. But first, here’s how to do it.

To use your Mac’s built-in Preview tool to compress PDFs:

• Open the PDF file with Preview.
• Go to File > Export.
• In the Quartz Filter dropdown, select ‘Reduce File Size’.
• Save the file with a new name to keep the original file intact (recommended).

Using the same 223 MB PDF mentioned above, this method reduced the file size to 192 MB, about a 14% smaller PDF.

Key advantages:

• Comes built into Mac
• No internet connection required

Although the Mac’s compression isn’t as robust as a dedicated PDF reducer tool, it does have its place. For example, if you need to upload an 11 MB PDF to a service with a 10 MB upload limit, Mac’s Export option might get your PDF size under the limit.

How To Compress a Large PDF with Native Windows Tools

If you’re a Windows user, you also have some free options. Windows doesn't have a built-in tool for compressing PDFs, but there are two workaround options you can try.

How to reduce PDF size on Windows using Microsoft Print to PDF:

1. Open the PDF in any PDF reader (e.g. Microsoft Edge browser).
2. Select Print and choose ‘Microsoft Print to PDF’ as the printer.
3. Click “Print”, then save the file with a new name.

In my experience, this option has been hit or miss. When trying the same large photo book PDF above, for example, the returned PDF was essentially the same size as the original. This method can sometimes reduce the file size, but it depends on the content of the PDF and is less predictable.

Another option on Windows is to convert your PDF to an MS Word document, then resave the document as a PDF.

How to reduce PDF size on Windows using Microsoft Word:

1. Open the PDF in Microsoft Word (this converts the PDF to an editable Word document).
2. Go to File > Save As.
3. Choose ‘PDF’ as the file format.
4. Before saving, select ‘More’ options.
5. In the options dialog, select ‘Minimum size (publishing online)’.
6. Click to save the file.

Because this method first converts your PDF to a Word file, it works best for documents with a very simple layout and minimal images.

Key advantages:

• Comes built into Windows
• No internet connection required

As mentioned, the main drawback of both of these options is the unpredictable result. These conversions are also much slower than an online PDF compressor. However, we thought it was useful to mention that these options do exist if you want to experiment.

→ If you’re looking for a simpler way to convert a PDF to Word, try our PDF to Word Converter tool absolutely free.

Smaller PDFs on Any Device

No matter what device you’re using, it’s easy to compress a large PDF into a smaller file size.

The local options on Mac and Windows aren’t the most reliable or predictable, but they may help out for some use cases. So experiment and see if they work for you.

If you need to quickly shrink a PDF, with a user-friendly interface and high-quality output, the button below will help you do that safely and securely in seconds.