Manatee

How to make a PowerPoint or Word file smaller on a Mac

· 6 min read

Nearly all of the weight in an oversized Word document or PowerPoint deck is pictures, and in decks, embedded video. The fastest fix on a Mac is File, then Reduce File Size in Word or PowerPoint, which downsamples every picture and throws away cropped-off areas; after that, re-insert any video as a compressed MP4 and save as a fresh copy. If the recipient only needs to read the file, export it to PDF and shrink that instead.

Find out what is taking the space

A .docx or .pptx is a zip archive with a different extension. You can look inside without any extra software.

  1. In the Finder, duplicate the file (Command-D) so you are working on a copy.
  2. Rename the copy so it ends in .zip instead of .docx or .pptx, and confirm the change.
  3. Double-click the .zip to expand it.
  4. Open the resulting folder and look in word/media (for Word) or ppt/media (for PowerPoint). Sort by size.

This tells you what you are dealing with. A 60 MB deck with a 45 MB .mp4 in ppt/media needs a different fix than one with two hundred 2 MB screenshots. Pasted images are often stored at full camera resolution even when they are displayed as a thumbnail, which is why a few photos can add up to more than the rest of the document combined.

Delete the expanded folder and the .zip when you are done; they were only for looking.

Step 1: reduce picture size inside Word or PowerPoint

Both apps have a built-in picture compressor on the Mac.

  1. Open the document and choose File, then Reduce File Size.
  2. Pick a picture quality. “Best for sending in e-mail” or the 150 ppi option is right for anything that will be read on screen; choose a higher setting if it will be printed.
  3. Leave “Delete cropped areas of pictures” checked. When you crop a picture in Office, the hidden part is still stored in the file until you do this.
  4. Choose whether to apply to all pictures or only selected ones.
  5. Click OK, then save the file under a new name with Save As, so you keep the original at full resolution.

If you would rather handle one picture at a time, select it, open the Picture Format tab, and click Compress Pictures. The options are the same.

Two things this will not fix: images pasted as vector drawings (charts from another app, for instance) are not pictures and will not be downsampled, and PNG screenshots with lots of flat color are already efficient, so they shrink less than photos.

Step 2: deal with embedded video and audio

When you insert a video into PowerPoint for Mac, the whole file is copied into the deck. A two-minute phone clip can be a few hundred megabytes on its own, and PowerPoint for Mac does not have a built-in media compressor to bring that down.

The approach that works is to compress the video first and insert the compressed version.

  1. Locate the original video. If you only have the copy inside the deck, expand the .pptx as described above and take it from ppt/media.
  2. Compress it. QuickTime Player’s File, Export As, 720p or 1080p produces an H.264 MP4 that PowerPoint plays well. If you want to hit a specific number, Manatee’s Shrink mode lets you type a target in megabytes and finds the quality that fits; 20 to 30 MB is plenty for a clip shown on a projector.
  3. In PowerPoint, delete the old video from the slide and insert the compressed file in its place (Insert, then Video, then Video from File).
  4. Save As a new copy.

Audio clips are rarely the problem, but the same method applies: convert a WAV to an M4A or MP3 before inserting it.

Step 3: clear out the leftovers

After pictures and video, these are the usual remaining causes of bulk.

  • Embedded fonts. In PowerPoint, choose PowerPoint, then Preferences, then Save, and check whether “Embed fonts in the file” is on. It can add tens of megabytes. Turn it off unless the recipient genuinely lacks the font.
  • Old format. A .doc or .ppt file can be larger than the same content as .docx or .pptx. Use File, then Save As, and pick the modern format. We have a separate guide for converting an old .doc to .docx.
  • Unused slide masters and layouts. View, then Slide Master; delete layouts nothing uses. Templates from design agencies often carry a dozen layouts with full-bleed background photos in each.
  • Hidden slides and leftover content. A hidden slide still carries its pictures. Delete what you do not need.
  • Save As instead of Save. Saving over a file many times can leave it larger than a clean write. Save As to a new name produces a fresh, compact file.

When a PDF is the better thing to send

If the person receiving the file does not need to edit it, a PDF is usually the right format: it looks the same everywhere and it compresses well.

  1. In Word or PowerPoint, choose File, then Export, and pick PDF. (File, then Save As, with PDF as the format works too.) Choose the “best for electronic distribution” option if you see one.
  2. Check the result. Office’s PDF export often preserves full-resolution pictures, so the PDF can be as large as the source.
  3. If it is still too big, drop the PDF into Manatee, choose Shrink, and name the size you need. A 10 MB cap for an upload portal or a 2 MB cap for a job application are both typical; Manatee finds the picture quality that fits and writes a new file alongside the original.

We cover the PDF side in detail in how to compress a PDF on a Mac.

What Manatee can and cannot do here

To be plain about it: Manatee’s Shrink mode works on video and PDF. It does not shrink a .docx or .pptx directly, because the right way to make those smaller is inside Word and PowerPoint, where the pictures can be downsampled without breaking the layout. Where Manatee earns its place in this workflow is the two steps around Office: compressing a video to a named size before you embed it, and shrinking the PDF you export at the end. It also repairs a .docx or .pptx that will not open, and strips author and revision metadata from Word files, but those are different problems.

Questions

Reduce File Size is grayed out. Why?

Usually because the document contains no pictures that PowerPoint or Word can compress, or because the file is still in a compatibility format. Save As .docx or .pptx first, then try again. In Word, the command is sometimes only available once a picture is selected; try Picture Format, then Compress Pictures instead.

Will compressing pictures make my printed handouts look bad?

At 150 ppi, a picture printed at a normal size on a page looks fine. If the deck is going to a print shop for large-format output, keep the original and send that version separately.

My Word document has no pictures but is still 20 MB. What else could it be?

Look inside with the .zip method. Common culprits are an embedded font, an embedded Excel chart that carries the whole workbook with it, or a document that was saved over hundreds of times. Copying all the content into a new blank document and saving that is a reliable last resort, and it also drops the revision history that travels with the old file.