Microsoft's support page for video transcripts and captions gives two different size limits for automatic transcript generation — 1GB in one section and 4GB in another, on the same page. The duration figure is identical in both places: 4 hours.
That is not a harmless inconsistency, because a long Teams meeting recording lands squarely between the two numbers. Which sentence you happened to read decides whether you expect a transcript at all.
The two statements, word for word
Under the heading Size limit and possible failures, the page says:
"The size limit for running automatic transcripts is 1GB and 4 hours. If the file size/duration exceeds this limit, you may want to find an alternative method for generating transcripts. Additionally, the automatic generation might fail if the language spoken in the video is either not supported or could not be recognized."
Further down the same page, under Supported file size:
"Transcript and closed caption generation are only supported for videos less than 4GB in size and less than 4 hours."
Both sentences are current on that page. The honest description is that Microsoft states two values; nothing in the documentation says which one supersedes the other, so treat the pair as the fact rather than picking a winner.
The limits, at a glance
| What | Official value | Source page |
|---|---|---|
| Automatic transcript limit (first statement) | 1GB and 4 hours | View, edit, and manage video transcripts and captions |
| Automatic transcript limit (later section, same page) | less than 4GB and less than 4 hours | same page |
| One Teams meeting recording file | 4 hours or 1.5 GB, then "the recording ends and automatically restarts" | Limits and specifications for Microsoft Teams |
| Microsoft's only size estimate for a recording | "The size of a one-hour recording is 400 MB" | Teams meeting recording and transcript storage |
| Uploading your own caption file | WebVTT only, and "Your file size exceeds the 4MB limit that this feature supports." | View, edit, and manage video transcripts and captions |
| Transcript download formats | ".docx or .vtt" | Start, stop, and download live transcripts |
| Codec, bitrate or resolution of a recording | not stated — check the official documentation | — |
Why a four-hour meeting falls exactly in the gap
Put the transcript page next to the recording page and the two numbers stop being abstract.
Microsoft publishes exactly one figure for how big a Teams recording is, in its storage planning guidance: "The size of a one-hour recording is 400 MB." Four hours of meeting at that rate is roughly 1.6 GB — above the 1GB figure, well below the 4GB one.
Run the same arithmetic the other way and the 1GB reading has a practical cutoff of about 2.5 hours. That is a calculation, not a published number: Microsoft does not say what resolution, bitrate or type of content the 400 MB assumes, nor whether it is an average or a ceiling. A screen-share-heavy hour and a camera-heavy hour will not weigh the same.
There is a second consequence that needs no estimate at all. A single Teams recording file cannot exceed 1.5 GB, because the limits page states the recording "ends and automatically restarts" at "4 hours or 1.5 GB" — either ceiling alone, not both. So:
- Under the 4GB reading, no Teams meeting recording is ever too large. It cannot be. The 1.5 GB split guarantees it.
- Under the 1GB reading, any recording that ran past roughly two and a half hours is over the line.
The 4-hour duration figure is the one part both sections agree on, and a recording file cannot exceed that either, for the same reason. Size is the only side of this limit where the two readings disagree, and it is the only side that can actually bite you.
Plan around 1GB
Pick the conservative number. The asymmetry is obvious once stated: if you plan for 1GB and the 4GB figure is the operative one, you compressed a file you did not have to. If you plan for 4GB and the 1GB figure is operative, you discover a missing transcript after the meeting is over and the room has emptied, which is the one situation you cannot redo.
Microsoft's own advice when a file exceeds the limit is to "find an alternative method for generating transcripts" — it does not name one. The lever you do have is the file itself.
Try it right here
Runs in your browser. Your file is not uploaded anywhere.
This runs entirely inside your browser tab: the file is read from disk, re-encoded locally, and handed back. Nothing is uploaded, which matters when the video in question is an internal meeting. If you want the individual controls rather than a preset, the full compressor exposes them, and how to compress a video without losing quality explains what bitrate and resolution actually cost you.
Scope: this is not the live transcription limit
Two different features get called "transcript" in Teams, and only one of them is governed by the numbers above.
The 1GB / 4GB statements sit on the page about videos stored in OneDrive and SharePoint — generating a transcript for a video file after the fact. Live transcription, started inside the meeting with Record and transcribe, is documented separately; the official pages we could find on live transcription do not give a size figure for it. If you need one, check the official documentation.
The two features also differ in what languages they cover. The same page lists eight languages for automatic transcription — "Chinese (Cantonese), Danish (Denmark), English (United States), French (France), Italian (Italy), Japanese (Japan), Portuguese (Brazil), Spanish (Spain)." — while a different section of that page says "Video owners can generate a transcript and captions file for videos spoken in 28 different languages and locales." Live transcription in meetings has its own, much longer list. Do not assume a language on one list appears on the others.
Other reasons generation fails that are not size
The language was not recognised. Straight from the same sentence as the 1GB figure: automatic generation "might fail if the language spoken in the video is either not supported or could not be recognized."
Transcription was off while recording was on. Microsoft is explicit about the result: "If recording is turned on, but transcription is turned off, the recording doesn't have a transcript file stored next to it. Also, when viewing the recording playback in Stream, captions can't be turned on." This is the official explanation for a recording that plays fine with no captions available.
Copilot was turned off for the meeting. The Teams admin pages carry this note: "When organizers turn off Microsoft Copilot in Teams meetings and events, recording and transcription are also turned off."
The file extension is not on the list. For generating captions on a video in SharePoint or OneDrive, Microsoft lists these: "mts", "m2ts", "ts", "3g2", "3gp", "3gp2", "3gpp", "asf", "wmv", "avi", "m4v", "mov", "mp4", "mp4v", "ogg", "webm", "movie", "mkv", "mpg", "mpeg". That list is scoped to caption generation — it is not the list of formats Teams chat accepts, and not the list Teams can play.
You cannot see the transcript file in the folder. By design: "There is no direct access to see or manage the captions and transcript file in the file explorer for OneDrive for Business or SharePoint." It is managed through the video player, not the file list.
FAQ
What is the size limit for Teams automatic transcripts? Microsoft's page states both "1GB and 4 hours" and "less than 4GB in size and less than 4 hours", in two sections of the same page. Plan against 1GB, since a missing transcript is discovered too late to fix.
Why didn't my long Teams meeting get an automatic transcript? Size is the likeliest reason. At Microsoft's own estimate of 400 MB per hour, anything past roughly two and a half hours is over the 1GB figure. Language recognition and transcription being switched off are the other documented causes.
Can I upload my own captions instead? Yes, but only as WebVTT, and the page names a ceiling in its error list: "Your file size exceeds the 4MB limit that this feature supports." Notes, comments and styles "are not supported and will be removed from the file upon upload."
Teams gave me a .vtt file and my editor wants SRT. Now what? Organizers and co-organizers can download a transcript "as a .docx or .vtt file" — those are the two formats Microsoft names. Convert with VTT to SRT rather than renaming the extension; the timecode punctuation differs between the formats.
Does splitting a recording help it get transcribed? Recordings already split themselves at 4 hours or 1.5 GB, and each resulting file is judged on its own. That is why the 4GB reading can never be exceeded by a Teams recording, and why the 1GB reading is the one worth planning for.
More on the same platform: the 4-hour and 1.5 GB recording gate and how Teams transcripts download as .docx or .vtt. Browse the rest of the platform limits we have documented, or see all Clapr tools — every one runs locally in your browser.
Figures cited from Microsoft's Teams limits, recording storage, transcription and video transcript documentation, checked 16 September 2026. Microsoft revises these pages; verify against the official docs before relying on them.
