Compress video for Slack

Slack lets a member or guest add files up to 1 GB, which is rarely the problem. To compress a video for Slack, type a smaller target such as 50 MB so it uploads and plays faster for teammates.

Limit 1 GB

05001000150020002500 MB

Drop a video here

MP4, MOV, M4V, WEBM, MKV, AVI

Up to 2 GB on a computer and 1 GB on a phone, because your device does the work. You can also paste a file.

Stays on your device
Your file is never uploaded
1 GB target
From Slack's own help page
MP4 out
H.264 video, AAC sound

How it works

To send video in Slack, choose the video you want to share in the channel. It is read on your device.
The default target is 1000 MB, which matches the Slack limit. Type a smaller size to make the file quicker for teammates to open.
The tool sets the bitrate from the target and the video length, leaving a small margin.
When the bitrate would be too low for a clean picture, the resolution is lowered first.
Each result is measured against the target. If it is still over, a lower bitrate is tried. Download the MP4 and drop it into Slack.

Facts

Slack: any file added by a member or guest: 1 GB. Checked 2026-11-12 Source
Why compress for Slack: Smaller files upload faster and open sooner for teammates in the channel
Target on this page: 1 GB by default. Type a smaller size, such as 50 MB, for faster uploads
Output format: MP4 with H.264 video and AAC sound
Where it runs: In your browser, on your device. Nothing is uploaded
Max file size: 2 GB on a computer, 1 GB on a phone
Browsers: Chrome and Edge 94 or later, Safari 16.4 or later, Firefox 130 or later on a computer

Questions

What is the file size limit for Slack?

A member or guest can add any file up to 1 GB to Slack. Compressing is only needed when a smaller file matters to you.

Why compress a video before posting it on Slack?

A smaller file uploads faster from your connection, and teammates can open and play it sooner. Typing a target such as 50 MB gives you that.

How do I get a video under 1 GB for Slack?

Keep the 1000 MB target, or type a smaller size, and press Compress video. Download the MP4 and add it to your Slack message.

Does the video leave my computer during compression?

No. Your browser compresses the file, so nothing is sent to a server while it works. The file only goes to Slack when you upload it there.