“File too big to email” — how to actually fix it on a Mac

First: what's the real limit you're hitting?

Worth ten seconds, because the fix is different for each. Gmail allows 25 MB per message (larger files get swapped for a Google Drive link automatically). Outlook.com and most corporate Exchange servers cap at 20 MB, and some IT departments set it lower. iCloud Mail allows 20 MB, with Mail Drop for anything larger.

Also note the receiving server has its own limit. A 24 MB attachment that leaves Gmail happily can still bounce off the recipient's 10 MB corporate mailbox. If you're emailing a large company, aim for under 10 MB and the problem disappears for good.

The free way, for one file

If this is a one-off, you do not need to install anything.

1. Video: open it in QuickTime Player → File → Export As → 720p (or 480p). A 5-minute iPhone clip usually drops from ~350 MB to ~40 MB. Still too big? Trim the boring first and last seconds — length matters more than resolution.
2. Photos: open in Preview → Tools → Adjust Size, set the width to 1600 px, then File → Export and drag the JPEG quality slider to about 70%. A 12 MB iPhone photo lands around 400 KB with no visible difference on a screen.
3. PDF: open in Preview → File → Export → Quartz Filter → Reduce File Size. Be careful — this filter is aggressive and can make scanned text mushy. Check page 1 before you send it.

None of this uploads anything. All three are built into macOS.

When the free way stops being free

The QuickTime and Preview route works fine until you're doing it for the fourth time this week, or for 60 files at once, or you need a specific target size rather than “smaller, hopefully”.

That's the gap this app fills: drop the folder in, pick “compress to under 20 MB”, and every file comes out under the limit in one pass — still without uploading a byte. The trim keeps the original quality instead of re-encoding the whole file, and the PDF compressor keeps text sharp because it recompresses the images inside the PDF rather than flattening the page.

Or: stop emailing the file at all

Sometimes the honest answer is that email is the wrong pipe. A 2 GB video is not going to become a 20 MB video without looking like a 2007 YouTube upload. Send an iCloud/Drive link, use Mail Drop, or hand over a WeTransfer link and keep the quality.

Compress when the file is 20–200 MB and needs to fit a limit. Link it when it's measured in gigabytes. Knowing which is which saves the most time of all.

Common questions

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