Compressing a video for Microsoft Teams

Microsoft Teams has three different file size limits depending on how the file travels, and they differ by a factor of 2,500. The one the interface invites you to use is the smallest.

The current figures and their source are here.

The three routes

How you send it	Limit
Attached to a chat message	100MB, max 10 attachments
Uploaded to a team's Files tab	250GB
Emailed to a channel address	under 10MB per attachment

The 250GB figure is the one Microsoft's documentation headlines, because files in the Files tab are stored in SharePoint and that is SharePoint's per-file limit. It is also the number that gets quoted in every summary of "Teams file size limit", which is why people are surprised when a 150MB video fails to attach to a message.

Which one you are actually using

If you dragged a file into the message box at the bottom of a chat, that is the 100MB route.

If you went to the Files tab of a channel and uploaded there, that is the 250GB route — and then posted a link to it, which is what Teams does automatically when you share from Files.

So the workaround for a file over 100MB is not to compress it. Upload it to the channel's Files tab and share the link from there. The file lives in SharePoint, everyone in the team can open it, and nothing was re-encoded.

That is genuinely the right answer for a 2GB training video or a large dataset. Compressing is the right answer when you want the file to be smaller, not merely permitted — which is most of the time, because a 500MB video in a chat is a bad experience for everyone who opens it on a phone.

The 10MB trap

The channel-email route is the one that catches people out, because it is almost invisible.

Every channel has an email address. Mail a file to it and each attachment must be under 10MB — a tenth of the chat limit and a twenty-five-thousandth of the Files limit. If you are forwarding a document into a channel from Outlook rather than attaching it in the app, that is the limit you are up against, and it is stricter than Outlook's own sending ceiling.

What fits in 100MB

100MB is generous for video, which is the pleasant surprise here:

Clip length	Bitrate available	Quality
1 minute	~13 Mbps	1080p60, excellent
5 minutes	~2.6 Mbps	1080p, good
10 minutes	~1.3 Mbps	720p comfortable
30 minutes	~440 kbps	480p, visible compression
1 hour	~220 kbps	360p, poor

A recorded meeting of an hour is the case that does not fit. Everything shorter than about ten minutes compresses comfortably at a quality nobody will complain about.

For screen recordings specifically — which is most of what gets shared in Teams — the bitrate needed is much lower than for camera footage. A slide deck being talked through is nearly static between transitions, so 720p screen content at 800 kbps looks clean where camera footage at the same bitrate would not.

Resolution before bitrate

The usual rule applies: do not keep 1080p and let the bitrate collapse. Below about 2 Mbps, 1080p starts to break down in motion and 720p at the same bitrate looks clearly better.

For a 30-minute recording into 100MB — 440 kbps — the right target is 480p, or better still, trimming the recording to the part people need. The bitrate floors by resolution are here.

Documents, not video

Most Teams attachments are documents, and those are easier:

• A text-based PDF is almost never near 100MB. If yours is, it has embedded photographs or save bloat. A structural rewrite often takes 30–70% off losslessly.
• A scan can easily exceed 100MB at 600dpi colour. Greyscale and 200dpi takes it to a few megabytes.
• A PowerPoint with embedded video is the common surprise. The video inside it is the file; compressing the video before inserting it is the fix.

The compliance angle, which matters in Teams more than elsewhere

Teams is corporate, and the files going through it are contracts, financials, personnel records and customer data. Sending any of those to a web compressor means uploading them to a third party's server for processing — which is a data transfer your organisation's policy probably has something to say about, regardless of what the compressor's privacy page claims.

Compress a video to 100MB, to 50MB or to 20MB runs entirely in your browser on your own machine's hardware encoder. There is no server in it and no upload, so there is no transfer to account for.

FAQ

What is the file size limit for Microsoft Teams?

It depends on the route. A file attached to a chat message is capped at 100MB with a maximum of 10 attachments. A file uploaded to a team's Files tab goes to SharePoint and can be up to 250GB. A file emailed to a channel's address must be under 10MB per attachment.

How do I send a file larger than 100MB in Teams?

Upload it to the channel's Files tab rather than attaching it to a message. That route goes to SharePoint with a 250GB per-file limit, and sharing from there posts a link that everyone in the team can open. No re-encoding and no compression needed — though a very large video is still a poor experience for anyone opening it on mobile data.

Why does Teams say 250GB but reject my 200MB file?

Because 250GB is the SharePoint limit for files uploaded to the Files tab, not the limit for files attached to a chat message. Chat attachments are capped at 100MB. The interface puts the chat attachment button in front of you, so most people meet the smaller limit first and the advertised figure looks wrong.

How long a video fits in 100MB?

About ten minutes at comfortable 720p, or five minutes at good 1080p. One minute fits at full 1080p60 quality with room to spare. Screen recordings do better than camera footage at the same bitrate because the picture is mostly static, so a talked-through slide deck can run considerably longer before quality suffers.