How to Compress a PowerPoint Under 25 MB for Email

Target size · 2026-08-25 · 4 min read

Every mail provider enforces an attachment ceiling: Gmail allows up to 25 MB per message, classic Outlook/Exchange servers commonly reject anything over 20 MB, and some corporate gateways cut it at 10 MB. When your deck is 60 MB, "please see attached" becomes a bounce notice.

The fast route: set a target, not settings

Instead of experimenting with quality sliders, tell the compressor the number you need:

  1. Open the free PPTX Compressor.
  2. Enable Compress to a target size.
  3. Drag the slider to 25 MB (or tap the Gmail / Teams preset).
  4. Drop your file. ByteSlim retries with progressively stronger settings until your file fits, then hands you the smallest result it achieved.

Which limit applies to you?

  • Gmail / Google Workspace: 25 MB total message size, after encoding.
  • Outlook.com: 20 MB per attachment; Exchange servers vary, often 10–20 MB.
  • Microsoft Teams / Slack: files are shared, not mailed, but per-file limits still apply (Teams: 250 GB cloud upload; Slack: depends on plan).
  • LMS platforms (Moodle, Canvas): frequently 10–50 MB per upload.

If you must go even lower

Target 10 MB or less? Expect the optimizer to lean harder on image re-encoding and downsampling. If a deck simply cannot reach the target without visible quality loss, the compressor keeps the best result found instead of failing silently — and the report shows exactly which images dominate the remaining size.

Your original file is never modified; compression always produces a new copy, and everything runs locally in your browser via privacy-first architecture.