How to compress files before sending them
Compression helps when you have many small files or uncompressed formats such as documents, RAW images, or WAV audio. It does almost nothing for video, JPEG, or MP3, which are already compressed.
Compressing a folder
- Put everything you want to send into one folder.
- Remove temporary files, duplicates, and unused exports.
- On Windows, right-click the folder and choose to compress it into a ZIP archive.
- On macOS, right-click the folder and choose to compress it.
- Check the resulting size before deciding whether compression was worth it.
- Upload the archive and share the download link.
What compresses well and what does not
| File type | Typical result |
|---|---|
| Documents, spreadsheets, text | Shrinks substantially |
| RAW photos | Shrinks moderately |
| WAV and AIFF audio | Shrinks moderately |
| CAD and 3D project files | Shrinks moderately |
| JPEG and PNG images | Almost no change |
| MP4 and MOV video | Almost no change |
| MP3 and AAC audio | Almost no change |
| Existing ZIP or RAR archives | No change |
When to skip compression entirely
If the material is video or already compressed images, zipping mostly wastes time and adds an extraction step for the recipient.
A transfer service removes the reason to compress in the first place: MyAirBridge sends up to 20 GB per transfer for free, and up to unlimited size on the Enterprise plan.
Practical advice
- zip many small files, upload large single files directly
- avoid split archives, a missing part makes the whole set unusable
- do not password protect the archive and then email the password alongside it
- name the archive so the recipient understands what it contains
FAQ
Does zipping a video make it smaller?
Practically no. Video formats are already compressed, so the archive will be almost the same size as the original.
Should I compress before uploading to a transfer service?
Only if you have many small files, where it speeds up the upload. For a few large files it adds an unnecessary step.
Is a password-protected ZIP secure?
It adds a layer, but the protection depends on the password and how it is shared. Transfer-level password protection and end-to-end encryption are easier to manage.
Summary
Compress documents and many small files, do not bother compressing video or photos that are already compressed. With transfer limits of 20 GB on the free tier, compression is often unnecessary rather than merely ineffective.