When you need 100 MB
100 MB is our quick-open size, not a Slack limit. It uploads fast and opens in the channel without a long wait. If your admin allows less, use the exact size box.
What to expect
A ten minute screen recording at 720p, or a few minutes of 1080p.
How much video fits in 100 MB
Worked out with the same maths the compressor uses, for a typical 1080p phone or screen clip with sound. Fast motion needs more room, still scenes and screen recordings need less.
| Clip length | Resolution we pick | How it looks |
|---|---|---|
| 10 seconds | 1080p | Sharp |
| 30 seconds | 1080p | Sharp |
| 1 minute | 1080p | Sharp |
| 2 minutes | 1080p | Sharp |
| 5 minutes | 720p | Sharp |
| 10 minutes | 540p | Good on a phone |
How we hit the number
We work out how many bits each second of video can use: the target size, minus a safety margin, divided by the length, minus the audio. Then we pick the largest resolution that still looks clean at that rate and encode with your browser's built-in video encoder. If the result is still over, we automatically try once more at a lower rate.
The target we aim for is 97.00 MB, which is 3.00 MB under 100 MB, so the file is not turned away over a few bytes.
Questions people ask
What is Slack's real limit?
Slack's help center states 1 GB per file. Workspaces can have their own storage and policy limits.
Should I post a link instead?
A link to a shared drive has no limit, but a file in the channel stays searchable and easy to find.
Related
- Shrink a screen recording before posting it in SlackDestination guide
- Compress a video to 100 MBVideo size
- Screen recording too big to share? Make it a small fileVideo size
Limits change. We link the official page wherever there is one, and the safety margin means a small change is unlikely to matter. Last updated 2026-11-09.