How to Compress a PowerPoint File

You finally put the finishing touches on your PowerPoint masterpiece, which includes a ton of great pictures and even a snappy video or two, but when you're ready to amaze your colleagues or boss, you find the file's too big to send by email. Bloating is a common problem with PowerPoint presentations that use lots of pictures or videos -- file size can easily exceed 50MB. You can reach a more manageable file size using PowerPoint's compression tools, which often shrink your files by as much as 90 percent.

Successful team of business people working on a laptop
Compressing audio and video files often improves playback speed.
credit: Yuri Arcurs/Hemera/Getty Images

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Start by making a copy of your presentation. This way you have a backup in case you bungle the compression process or you want to go back later and make edits to the full-quality original.

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Open the copy and double-click on any image. It doesn't matter which one -- you just want to make the Picture Tools ribbon appear. Select the "Compress Pictures" command in the ribbon's Adjust group.

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Remove the check mark next to "Apply only to this picture" in the dialog box. This causes PowerPoint to compress all the pictures in the presentation, not just the one you selected. Also, check the box next to "Delete cropped areas of pictures." This setting removes areas of pictures that are not visible on the screen but that are taking up space in the file.

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Select a target output of either 150 ppi or 96 ppi. PowerPoint already compresses files to 220 pixels per inch by default, so selecting this setting won't do any good. The 150-ppi setting reduces the size of the image files by about 80 percent without a noticeable loss in quality when you view it on a computer screen or through a projector. The 96-ppi setting gives you the best compression -- about 90 percent -- but the images may appear a little fuzzy or grainy. Click "OK" to compress the images.

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Save even more space by compressing video or audio files in your presentation. Media files are by far the biggest space hogs when it comes to presentation files; this is where you can generate the biggest reduction on your overall file size. To compress the files, click PowerPoint's "File" menu and then click the "Compress Media" button. If you don't see the button, it means your presentation doesn't have any media files to compress.

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Select "Presentation Quality," "Internet Quality" or "Low Quality" from the choices. The Low Quality setting gives you the most savings -- squeezing the video file to about 10 percent of its original size, but the videos appear a little fuzzy or grainy. The Internet Quality option also saves considerable space. It reduces the file size by more than half, with only a little loss in quality -- similar to what you might experience viewing a streaming video. The third choice, Presentation Quality, keeps videos at pretty much the same quality level, but only reduces the video file size by about 10 percent or so. Your actual mileage with each of the choices will vary, depending on the type of media file and its original size and compression type.

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Save your presentation as a PPTX file, which is the default file format for PowerPoint 2007, 2010 and 2013. The PPT file format used in older PowerPoint versions doesn't support compression. If your presentation is in the older PPT format, saving it as a PPTX file saves considerable file space without any additional steps.

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