Slack Video File Size Limit: 1GB, and What It Isn't

Slack publishes no video-specific file size limit. Video files fall under the same general upload cap, which Slack's help center states without qualification: "You can add files up to 1GB in size."

That sentence answers the question. People keep searching anyway because Slack attaches a second number to video — five minutes — that governs something entirely different. This page separates the two, lists every Slack video number with an official source, and is explicit about what Slack does not document.

The limits, at a glance

Every "not stated" row is deliberate. Numbers for those rows circulate on third-party blogs with no official source, so none are invented here — see official docs.

1GB and five minutes are two different limits

Slack's clips help page opens with: "Share audio and video clips up to five minutes long in Slack to communicate easily with your team, regardless of their time zone or location."

So:

• 1GB is a size limit on file uploads. It is what stops a large .mp4 from landing in a channel.
• Five minutes is a duration limit on clips. Clips are Slack's built-in recorded audio and video messages, which anyone in the channel or DM can play and reply to in thread. They are available on all plans, to members and guests alike.

Neither constrains the other. Slack publishes no duration limit for a video uploaded as an ordinary file attachment. A 40-minute screen recording under 1GB is, as far as the documentation goes, just a file. Five minutes never enters the picture.

The confusion has a real cause. Slack lists "Upload an existing video as a clip." as one of the clip options, so there genuinely are two routes for an existing video: as a file, or as a clip. What Slack's page does not say is which containers or codecs that clip route accepts, or whether a size or duration threshold applies to it. Treat that as unknown and check the official documentation.

One more clip detail: Slack notes that clips follow the same retention policy as other files, which matters on the free plan — see below.

What Slack does not tell you about video

Most pages skip this half, because "we don't know" makes for unsatisfying copy. But knowing where the documentation stops keeps you from planning around an invented number.

1. Duration for uploaded video files. Not stated. Only clips have a published duration limit.
2. Per-plan file size tiers. Slack's "You can add files up to 1GB in size." appears with no plan breakdown beside it — no Free / Pro / Business+ / Enterprise+ table for per-file size exists on that page. Claims that paid plans raise the per-file cap have no official source.
3. Video preview thresholds. Slack does document preview thresholds, but only for images and Office files: "If you share an image, the preview will only display inline if it's smaller than 25,000 pixels on the longest side, and less than 45 million pixels total. Microsoft Office files that are larger than 50 MB will not display a preview." The two image conditions are joined by and — both must hold, and failing either one means no inline preview. There is no published equivalent for video.
4. Transcoding. Slack says nothing about whether it re-encodes uploaded video, or at what point the size is measured. That gap matters: on Discord, the size check is documented as happening before compression, which changes how you prepare a file. Slack makes no such statement, so assume the file on your disk is the file being judged.
5. Which video formats play inline. Slack's developer docs publish a filetype enumeration including mp4, mov, mkv, webm, ogv, wmv, flv and mpg. That describes how Slack labels a file's type — not a promise that those containers play inside a message. No official page lists an inline-playback whitelist for video.

Also keep preview and upload separate: those pixel and 50 MB figures describe display behaviour, not whether a file uploads. The upload ceiling is still 1GB.

What to do when a video won't fit

There is one real answer at 1GB: make the file smaller before Slack sees it. A gigabyte is generous for anything watched in a chat window, so if you are over it, the source is almost certainly a screen recording or camera export at a needlessly high bitrate.

Try it right here

Runs in your browser. Your file is not uploaded anywhere.

Loading tool…

This runs entirely in your browser tab: the video is read from disk, re-encoded locally, and handed back. Nothing goes to a server, which matters when the recording is internal and headed for a private channel.

If the source is a QuickTime file off a Mac or iPhone, MOV to MP4 does the container change the same way. For long recordings where only the conversation matters, extracting the audio collapses the size problem entirely. To pick settings yourself, how to compress a video without losing quality covers which knobs actually move file size.

Gotchas that have nothing to do with size

Zipping a large video for a Slack Connect channel makes things worse. Slack blocks a list of file types in Slack Connect conversations — "To help keep Slack secure, certain types of files cannot be added to Slack Connect channels and direct messages (DMs)." That list includes .7z, .gz and .tar. It does not include .mp4, .mov, .mkv or .webm. So the archive you built to "package" the video gets rejected while the raw video would have gone through. Mind the boundary: this list applies to Slack Connect channels and DMs, not to Slack as a whole.

Your admin may have set a stricter cap than 1GB. Slack's developer docs define file_upload_size_restricted as "The size of provided file is too large, as the team has restricted uploads of large files." If a file well under 1GB is refused, a workspace-level restriction is live — the docs don't say where that setting lives, so ask an owner or admin.

Uploads also fail for reasons unrelated to size. Slack: "Files you add to Slack will be scanned for viruses and other malware, and won't be uploaded if any are detected."

On mobile, you cannot save a colleague's video. Slack: "On your mobile device, you can only download image files."

Slack's developer docs mention a 5GB free-team storage error. The storage_limit_reached entry in that error-code reference reads: "File storage limit has been reached. This occurs when free teams have uploaded 5GB of files." Three qualifications matter: 5GB is the workspace's total file storage, not a per-file cap; its source is a developer error-code reference and a 2019 changelog, not a current user-facing help page; and the help center's free-plan article talks about time windows rather than capacity.

On the free plan, time deletes your videos, not size. Slack: "You can view and search messages and files from the last 90 days. Files include things like clips, PDFs, documents, images, screenshots, and audio and video files." Content past 90 days is hidden, and upgrading restores it — "the remaining 275 days will become available should you upgrade to a paid plan." Content more than one year old is permanently deleted: "It will not be possible to restore messages and files once deletion occurs."

There is a trap inside that. If a Workspace Owner chose the retention option to delete messages and files after 90 days, then per Slack, "this will automatically delete any that become hidden by the message and file limit." Content that would normally return on upgrade is gone instead. Check that setting before assuming an upgrade rescues an old recording.

FAQ

What is the Slack video file size limit? There isn't a video-specific one. Video uses the general file upload cap, which Slack states as "You can add files up to 1GB in size." Slack does not publish separate per-plan caps for file size.

How long can a video be on Slack? Clips are capped at five minutes. For a video uploaded as a regular file, Slack's documentation states no duration limit at all — under 1GB, length is not something Slack says it checks.

Does Slack compress or reduce the quality of uploaded videos? Slack's documentation doesn't say — there is no official statement about transcoding, or about whether size is measured before or after any processing. Plan on the file you upload being the file that counts, and check the official documentation if you need confirmation.

Why can't I upload my video to a Slack Connect channel? If you zipped it, that is likely the reason — .7z, .gz and .tar are on Slack's restricted list for Slack Connect channels and DMs, while common video containers like .mp4 are not. Malware scanning and workspace-level upload restrictions are the other two documented causes.

Do videos on a free Slack workspace get deleted? Yes, on a schedule. Files older than 90 days are hidden and restored if you upgrade; content more than one year old is permanently deleted and cannot be recovered. Clips follow the same retention policy as any other file.

My file is under 1GB and Slack still refuses it. What now? Check three things: whether the extension is on the Slack Connect restricted list, whether an admin tightened the upload size, and whether the file tripped malware scanning. Slack documents all three as failure paths separate from the 1GB cap.

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Compressing before you upload is the one step that works against any of these limits. The compressor and the rest of the Clapr tools run in your browser, so nothing leaves your machine. For neighbouring questions, see Slack's general file upload limit and WhatsApp's video size rules.

Figures cited from Slack's official help center and developer documentation, checked 16 September 2026. Verify against the official pages before relying on them.