Compress a video for Slack
Slack's limits are storage limits rather than send limits, and the storage is not yours: it belongs to the workspace and everybody in it. That, and the fact that nearly every video posted to Slack is a screen recording, makes this a different problem from the rest of this site.
Drop your video here
or click to browse — MP4, MKV, MOV, WebM, AVI and more
Preset to a 20 MB ceiling for Slack. Change it in the target field if Slack has moved the number since — the tool solves the bitrate from whatever you type.
Two limits, and the one that matters is not per file
The per-file cap is generous enough that most people never meet it. The one that bites is the workspace storage total: paid plans grant an allowance per member which is pooled across the whole workspace, and the free plan has a fixed limit of its own. Your 800 MB recording does not come out of your quota, because you do not have a quota. It comes out of everyone's.
That produces a failure mode nothing warns you about. No upload is rejected. The workspace simply fills up over a year of everybody posting untouched screen recordings, and then an administrator spends a Friday afternoon deleting other people's files to make room. Check where your workspace stands in its admin settings rather than assuming, and if you cannot see that screen at all, take it as a reason to be conservative on somebody else's behalf.
| Clip length | Video bitrate budget | Realistic resolution |
|---|---|---|
| 15 seconds | 10,609 kbps | 1080p or original |
| 30 seconds | 5,240 kbps | 1080p or original |
| 1 minute | 2,556 kbps | 1080p |
| 2 minutes | 1,214 kbps | 720p |
| 5 minutes | 440 kbps | 480p |
| 10 minutes | 204 kbps | 360p |
| 30 minutes | — | Not viable |
On the free plan it disappears anyway
Free workspaces keep only a rolling window of history, and files fall out of reach along with the messages that carried them. The length of that window has been changed before and is a plan detail rather than a law of nature, so look it up on Slack's own pricing page if the answer matters to you.
It changes what you should do with a recording, though. If somebody needs it next quarter, Slack is not where it lives: put it somewhere durable and post a link. If it is a "here is the bug, watch what happens when I click this" clip, compress it small, post it, and let it expire on schedule. Those are two different files and it is worth deciding which one you are making before you export.
Screen recordings compress strangely, in your favour
Almost everything posted to a Slack channel is a screen recording: a bug reproduction, a walkthrough of a dashboard, a demo of the thing you finished this morning. That is unusual footage, and some of the advice on the rest of this site is wrong for it.
H.264 encodes the difference between one frame and the next, and on a screen recording most frames are identical to the one before. A cursor moves, a character appears in a text field, and the rest of the picture is reused for nearly nothing. Five minutes of a mostly static screen costs a fraction of what five minutes of handheld camera footage costs at the same resolution and the same settings.
The expense is concentrated in the moments when the whole frame changes at once, and every recording anybody makes contains the same three: smooth scrolling, switching windows, and a video playing inside the thing being recorded. Scrolling is the single most expensive second of a screen recording. Page down instead of dragging, cut the dead air where you were hunting for the right tab, and the file gets smaller before you have compressed anything at all.
Keep 1080p and lower the bitrate instead
The reason to record a screen is almost always that somebody has to read something on it, which makes downscaling the wrong lever here. This is the opposite of the advice on every other platform page on this site. Dropping 1080p to 720p removes the pixels that letterforms are made of, and no bitrate afterwards puts them back; text goes from sharp to soft and stays soft.
A low bitrate on the same content is far more forgiving. When the picture holds still the encoder keeps refining the same frame, so static text survives a budget that would destroy moving footage. A static 1080p screen recording holds together at something like 800 kbps, roughly 6 MB a minute, and the 20 MB preset above carries about three minutes of it. Leave the resolution at 1080p or original and let target mode solve a bitrate that would look alarming on a camera clip. The email page makes the same argument for the same reason.
A screen recording is a recording of your screen
The thing about a bug repro is that it captures whatever else was on the monitor: the Slack sidebar with your private channel names down one side, a customer record you were testing against, an internal dashboard, the name of an unannounced project sitting in a browser tab. It is the most casually produced and most quietly sensitive video most people ever make.
Uploading that to a free compression site to save a few megabytes in a channel is a poor trade. Here the encode runs inside the tab on your own CPU and the file is never transmitted, which you can confirm in the network panel or by going offline once the page has loaded. More on that, including how to verify it.
Questions about Slack
What is the file size limit for video on Slack?
The per-file cap is generous; the limit that actually matters is the workspace storage total, pooled across every member on paid plans and fixed on the free plan. Check the workspace usage in its admin settings, because a file you upload counts against everybody rather than against you.
How long do Slack files stay available?
On paid plans, for as long as the workspace keeps them. On the free plan only a rolling window of history is reachable, and files disappear from view with the messages that carried them. That window is a plan detail which has changed before, so check Slack's pricing page. Anything that has to outlive it belongs somewhere else, with a link posted in the channel.
How do I compress a screen recording without the text going blurry?
Keep the resolution. Downscaling destroys text permanently, while a low bitrate on a mostly static screen is nearly harmless because the encoder holds and refines the same frame. Export at 1080p and set a low target size rather than dropping to 720p.
Elsewhere on the site
Slack is one of 7 destinations with a page here, and the other 6 differ from the Slack page only in the ceiling the compressor opens at and in what that particular platform does to your file after you send it. The full list is here, or jump straight to one:
Or go straight to a size ceiling: