Does Instagram Reels support WebM files?
an open, web-native format that produces smaller files at a similar quality, popular for embedding on websites
WebM is not in Instagram's published video specs, which list MOV and MP4. Convert to MP4 before uploading.
Meta's Instagram video specs list MP4 and MOV, and Instagram's publishing API requires MOV or MP4. The Instagram app may still take a WebM file on some devices, but nothing documents it; an MP4 with H.264 video and AAC audio is the safe choice for Reels.
Recommended upload: MP4 with H264. WEBM is not the platform's documented upload container; export as MP4 with H264 video for the safest upload.
Convert WebM to MP4 →Source: Instagram API: Reel and video specifications. Instagram API publishing spec (MOV or MP4, H.264/HEVC, AAC); Meta's Instagram video ad specs also list MP4 and MOV. Checked 2026-10-05.
Frequently asked
Does Instagram Reels support WebM?
WebM is not in Instagram's published video specs, which list MOV and MP4. Convert to MP4 before uploading. Meta's Instagram video specs list MP4 and MOV, and Instagram's publishing API requires MOV or MP4. The Instagram app may still take a WebM file on some devices, but nothing documents it; an MP4 with H.264 video and AAC audio is the safe choice for Reels.
What format should I convert WebM to for Instagram Reels?
MP4 - a widely supported video container; acceptance also depends on the video and audio codecs inside it. Converting WebM to MP4 runs entirely in your browser with the converter linked below.
How do I check whether my WebM file will upload cleanly to Instagram Reels?
Open the Koldflux File Doctor, drop in the file, and pick Instagram Reels. It reads the container, codec, resolution, duration and file size locally and reports pass / warn / fail against the documented Instagram Reels constraints.