PDFs are great if you want to share documents across multiple platforms, all without worrying how the format will display on Windows, Mac, phone or tablet.

They're also perfect if you need people to add information to a file without being able to change or edit it.

One downside is that the size of the files can be substantially bigger than a comparable Word or PowerPoint document.

Fortunately, if you're stuck with a massive PDF that is making it impossible to email to people, there are ways to make reduce that file size.

How can I compress a PDF online?

A quick and easy way to make PDF files smaller is to visit one of the free websites that offer this service. A few popular options include PDFBear, SmallPDF, PDF Compressor, PDF2Go, and I Love PDF. Here, we are using the latter but they all work in a similar way.

1. Head to the website either click the Select PDF Files button or if you have the file to hand you can click and drag it onto the area around the button.

how to reduce pdf file sizes

2. After clicking Select PDF Files you’ll see an Explorer window open up which you can use to navigate to the PDF. When you find the one in question, highlight it and click Open.

how to reduce PDF file sizes

3. The PDF will now appear in the centre of the screen with three options listed below. These are Extreme Compression, Recommended Compression, and Less Compression.

The higher the level of compression, the lower the size of the file, but this will also be accompanied by lower quality images. Depending on the nature of the PDF, select the appropriate level then click on the Compress PDF button found underneath the list.

how to reduce PDF file sizes

4. The site will now go about reducing the size of the file. Once this is done you’ll see a message confirming the process is over and a button marked Download compressed PDF.

Under the button there will also be an indicator of how much the file size has been reduced. In our case, after choosing the Recommended Compression option, the PDF was 51 percent smaller than the original.

how to reduce PDF file sizes

5. Click the Download compressed PDF button and you’ll soon be in possession of a diminutive file that can be more easily shared online.  

How to compress a PDF using Adobe Acrobat

If you have a subscription to Adobe Acrobat DC then you’ll be able to make use of the built-in optimisation tool that reduces file sizes. Those not paying for the service can still access the feature by taking out a seven-day free trial.

how to reduce PDF file sizes

Once you have the software installed and running, open the PDF in Acrobat and navigate to File > Save as Other > Optimised PDF. This will then create a smaller version of your file. You can also use Tools > Optimise PDF.

Should you wish to edit your PDF document further then it can be worth investing in a dedicated software package. Check out our recommendations of the best PDF editors.