Calculate file size from bitrate
Have a video bitrate instead of a target file size? Reverse the estimate using duration and audio bitrate.
How the bitrate estimate works
The calculator converts the target size into total bits, divides by duration, then subtracts the selected audio bitrate to estimate the video bitrate budget.
Bitrate and perceived quality
Bitrate alone does not determine quality. Codec efficiency, source detail, motion, frame rate, encoder settings and repeated encoding all influence the visible result.
Allow room for variation
Real files include container overhead and may use variable bitrate. For a strict upload limit, target a slightly smaller size than the maximum.
Choosing audio bitrate
Speech can often use a smaller audio bitrate than complex music. Reserving more bitrate for audio leaves less of a fixed target size available for video.