Loom's Chrome extension encodes into a WebM container on Loom's side, while every video downloaded from Loom is described by Loom as an .MP4 file. Those are two separate layers, and almost every article on this question collapses them into a single answer.
The difference is not academic. It decides what codec your recording was captured in, how many audio channels you get, what resolution ceiling applies, and what you can hand to an editor afterwards.
What Loom records: two recorders, two containers
Loom publishes a per-platform encoding table in "Loom video encoding settings (by platform)". The page opens by saying it "provides details about video formats, adaptive streaming (HLS), Dynamic Adaptive Streaming over HTTP (DASH), and the expected encoding for videos recorded with the different areas of the Loom platform."
Here is what that table says, row by row:
| Chrome extension | Desktop app (Mac and Windows) | |
|---|---|---|
| Container | "DASH with WebM" | "HLS with TS" |
| Video codec | "VP8/VP9" | "H.264" |
| Audio codec | "OPUS" | "AAC, 48kHz" |
| Resolution | "Up to 1080p video" | "Up to 4K video (360p, 480p, 720p, 1080p, 1440p, 2160p)" |
| Frame rate | "Target 30fps" | "Target 30fps" |
So the answer to "does Loom record WebM or MP4" depends entirely on which recorder you used. The extension path is VP8/VP9 video with OPUS audio in WebM. The desktop path is H.264 with AAC, delivered as HLS with TS segments.
Two details from the same table are worth pulling out.
The 30fps figure is a target, not a guarantee. Loom says directly: "Loom's Chrome extension and desktop app target 30fps on average. However, operating system settings, hardware specifications, and system load might affect the actual frame rate Loom can capture."
Desktop audio differs by operating system. The Windows desktop row reads "Channels: 1 Channel (Mono)"; the Mac desktop row reads "Channels: up to 2 Channel (Stereo)". Loom's page lists both specs without commenting further. If a Loom recording made on Windows sounds centred and flat compared with a colleague's Mac recording, that documented row is the first place to look.
What you actually download: MP4, on every page that mentions it
Three separate Loom pages state the download format, and they agree.
The encoding page ends with: "Note: All videos downloaded from Loom will be in a .MP4 format. The MP4 media encoding specs are similar to the RAW media recorded." The download article says: "When you download a Loom, it is downloaded in the .MP4 format ." The upload article repeats it: "All videos downloaded from Loom will be in a .MP4 format."
Two things follow from this.
First, the WebM container appears only in the specifications table describing how Loom stores and streams extension recordings — the pages that describe downloading all name .MP4. If you specifically need the underlying WebM, check the official documentation rather than assuming the Download button produces one.
Second, note Loom's exact wording: the MP4 specs are "similar to" the raw media, not identical to it. An extension recording captured as VP8/VP9 with OPUS audio is not the same bitstream as the MP4 you save. The official pages we could find do not give the transcode parameters, so do not assume the download is a lossless copy of what your browser captured — check the official documentation if you need the exact specs.
Why the container explains the quality that keeps shifting
This is where the WebM answer becomes useful rather than trivial. Loom uses two different adaptive streaming systems, matched to the two containers.
For desktop recordings: "Loom uses HTTP Live Streaming (HLS) to deliver the best quality version of your video recorded with the Mac and Windows desktop apps ." For extension recordings: "Loom uses Dynamic Adaptive Streaming over HTTP (DASH) to deliver the best quality version of your video recorded with the Chrome extension ."
Both work the same way. DASH, Loom explains, "works by breaking the content into a sequence of small segments, which are served over HTTP." The player then picks between those versions on the fly: "The Loom web player will automatically choose the highest-quality version of the video that your internet connection can support. As your available bandwidth fluctuates, the quality of the stream will adapt to ensure continuous playback without buffering. This is why you sometimes see the playback quality change."
That is the official explanation for the "my Loom looks blurry" complaint, and it is about delivery, not about your recording. One related limitation from the playback-quality page: "The video quality selector is not available for video's that have been trimmed or stitched at this time."
If you have a WebM file and need it in an editor
For uploading into Loom, the supported container list is published verbatim as: "Supported containers: MV, AVI, WEBM, MP4, MOV (Up to 4GB)". WebM is on that list. Loom also caps uploads: "Loom limits uploads to 4 GB or 12 hours, whichever is less." A file that fails will often show a specific message, and Loom names the usual causes: "You may receive a Failed to process message after attempting to upload a video. This most often occurs because the file is over 4 GB, its frames per second are over 60, or its resolution is over 4096 x 2160."
When an upload is rejected anyway, Loom's own advice is to re-encode: "If the file you want to upload to Loom is not supported or you believe it should be supported but is being rejected, try running your video through Handbrake . There are times when an underlying property of your video is not supported (like the number of audio channels is too high) and this can only be fixed by running the media through Handbrake." Loom's recommended target is explicit — it suggests "exporting your video using the media specifications in the above table (H.264/AAC to . MP4 file.)"
That is exactly the conversion below, without installing anything:
Try it right here
Runs in your browser. Your file is not uploaded anywhere.
It runs in your browser tab: the file is read from disk, re-encoded locally and handed back, so nothing is uploaded anywhere. If you need the reverse direction for a web project, MP4 to WebM is the same tool pointed the other way, and the full set lives at all Clapr tools.
Before you count on the download at all
Downloading is gated by plan and role. Loom states: "The download feature is only available on Business, Business+ AI, or Enterprise plans. Users on the Starter Free plan can't download videos," and adds that "Creator Lite and Viewer roles don't have download permissions on any plan." For viewers, permission is conditional in a way that catches people out: "Viewers who are not signed in to Loom or have the Starter free plan will not be able to download your video regardless of your video settings."
Three more facts about the MP4 you get:
- There is a size ceiling. "you won't be able to download Loom videos over 20GB. (How big is 20GB? Approx. 3 hours recorded in 4K)."
- Captions do not travel with it. Loom lists what is dropped: "other Loom features, including CTAs, Filler Word + Silence removal, Chapters, and Closed Captions, will not be included in the downloaded file." (Note that the filler-word article states the opposite for its own feature — "If you download your video, the removal will remain intact" — so check both pages for your case.)
- The framing can change. "Our web player adjusts the aspect ratio of a video to 16:9 (1280 x 800), which makes the video appear proportional. However, when you download a video, it is in the original aspect ratio the video was recorded in."
If plan limits are the real blocker, the related write-up on Loom's 5-minute recording limit covers which roles are restricted and why paid workspaces still hit it. More format walkthroughs are collected under guides.
FAQ
Does Loom record in WebM or MP4? Both, depending on the recorder. Loom's encoding table lists the Chrome extension as "DASH with WebM" with VP8/VP9 video and OPUS audio, and the Mac and Windows desktop apps as "HLS with TS" with H.264 and AAC.
What format is a downloaded Loom video? MP4. Loom states on three separate pages that downloads are in .MP4 format, and adds that the MP4 encoding specs are "similar to the RAW media recorded" — similar, not identical.
Why is my extension recording capped at 1080p? The encoding table gives the Chrome extension "Up to 1080p video" against "Up to 4K video" for the desktop apps. Asked whether the extension can record HD on paid plans, Loom answers: "Unfortunately, no. This is a limitation of Chrome and one of the reasons we built the desktop app."
Can I upload a WebM file into Loom? WEBM is on Loom's published container list, subject to the 4 GB limit and the processing thresholds above. If it is rejected, Loom's advice is to re-encode to H.264/AAC in an MP4 file first.
Does the downloaded MP4 include subtitles? Loom's download page lists Closed Captions among the features that "will not be included in the downloaded file." Captions are available separately as an SRT download, which Loom limits to creators and admins on Business/Business + AI plans and members and admins on Enterprise.
Specifications quoted from Loom's help centre, checked 18 September 2026. Loom's pages have disagreed with each other before — verify against the official documentation before relying on a figure.
