Compress Video for Slack's Upload Limit
Slack's per-file limit is 1 GB on every plan, so most videos upload fine. The problem is usually the workspace's shared storage quota, which on the free plan is small and shared by everyone — a few 4K screen recordings and the team is out of room.
The limits that actually bite
| Constraint | Value |
|---|---|
| Per file | 1 GB |
| Free plan storage | 5 GB for the whole workspace |
| Pro plan storage | 10 GB per member |
| Slack clips (recorded in Slack) | 3 minutes on free plans |
Screen recordings are the main offender
A 4K screen recording of a twenty-minute session can run into several gigabytes, and almost none of that resolution is useful: text on a 1080p rendering of a 4K screen is still perfectly readable, because screen content is mostly flat colour and sharp edges — exactly what compresses well.
For screen capture specifically:
- 1080p, always. Record at 4K only if you need to zoom in later.
- Low frame rate is fine. 15–24 fps is plenty for a walkthrough, and it nearly halves the size against 30.
- Quality Balanced, not Small. Text goes illegible before photographic detail does; do not starve it.
Practical targets
Under 25 MB for anything posted in a busy channel — it previews instantly and does not make people wait. Under 100 MB for a recorded demo. Past that, put it in Drive and post the link: Slack storage is shared, and a 700 MB file in #general is everyone's problem.
Keep it playable in the Slack client
MP4 with H.264 and AAC plays inline in Slack on every platform. HEVC frequently does not — it shows as a file to download instead of a video to watch, which defeats the point of posting it in a channel. The default here is H.264 for exactly that reason.
Compress a video to 25 MB → Runs in your browser. Nothing is uploaded.