Video File Size Calculator

File size in megabytes equals the bitrate in megabits per second times the duration in seconds, divided by 8. There are 8 bits in a byte, so a 10 Mbps clip uses 1.25 megabytes per second.

Bitrate is measured in bits while file size is measured in bytes, and one byte is 8 bits. Dividing megabits by 8 converts the stream rate into a storage size.

It uses decimal units, so 1 GB is 1000 MB. That matches how storage capacity and most streaming guidelines are quoted.

Use the total bitrate that combines video and audio if you want the full size. If you enter only the video bitrate, add the audio bitrate to it first for an accurate result.

Variable bitrate encoding, container overhead and changing scene complexity all shift the true size. This estimate assumes a steady average bitrate, which is close for most exports.