Estimate video size before exporting
A SaveContentMe guide · Updated
Estimate video file size
Estimated size:
MB = (video Mbps + audio kbps ÷ 1000) × seconds ÷ 8. This estimates average bitrate and excludes container overhead. The calculation runs in your browser.
Duration and average bitrate determine size
Bitrate measures data per second. Add the video and audio rates, multiply by duration in seconds and divide by eight: a byte contains eight bits. The calculator uses decimal MB, where 1 MB is 1,000,000 bytes.
For example, one minute at 10 Mbps with 128 kbps audio is approximately 75.96 MB. Five minutes at those settings is 379.8 MB. The files differ fivefold even though the export resolution and quality settings match.
Working within a size limit
First decide whether you need the entire recording. Trimming an unnecessary beginning or ending reduces size without changing the retained portion's quality. Then make a separate copy at a lower average bitrate. Compare it with the original, especially movement and small lettering.
A five-minute file under 100 MB needs a total average bitrate below 2.67 Mbps. With 128 kbps audio, roughly 2.54 Mbps remains for video before container overhead. Leave some margin and keep your original separately.
Why the actual file may differ
The calculator does not inspect a clip or choose its quality. At variable bitrate, detailed scenes and movement can consume more data than a still picture. The whole file's average matters, rather than a peak figure.
The container, additional audio tracks, captions and metadata also use space. For a strict limit, check the finished file's size before sending. Your inputs stay in the browser, and no video upload is needed for this calculation.