How do I make a video small enough to e-mail?
Drop the file — the target size is set to 20 MB, below the 25 MB mark the big providers allow per message. Cap the height at 720p, export, attach the file. Compression happens in your browser: the recording passes through no third-party server, which is what matters for confidential material.
How big may an attachment really be?
Gmail allows 25 MB per message for personal accounts (Google Gmail Help, "Send attachments with your Gmail message"). Exchange Online and Microsoft 365 also default to 25 MB, and the administrator can set anything between 1 MB and 150 MB (Microsoft Learn, "Exchange Online limits", checked in July 2026). So 25 MB is a safe assumption — but the recipient's server may be stricter.
Why is the preset 20 MB and not 25?
Because an attachment is re-encoded as text for transport. The usual base64 scheme turns 3 bytes into 4 characters, roughly 33 percent overhead, and headers plus message body add to that. A 20 MB file therefore lands close to a hard 25 MB message limit. If your provider or the recipient's is strict, set the target to 15 MB and you keep enough headroom.
What if the video is still too big?
Trimming has the strongest effect, then 480p instead of 720p, then dropping the audio track. If none of that is enough, a link is the honest answer: most providers turn oversized attachments into a cloud link automatically anyway. For anything beyond a few minutes that is the better route — also for the recipient, whose mailbox does not fill up.
Honest limits
An encoder only approximates its target, so the finished file is measured and a missed target is reported. Processing takes roughly as long as the video runs and the tab has to stay open. The attachment itself is transferred unchanged: unlike messengers, e-mail does not compress your video a second time.