Estimate a video’s storage size from its average bitrate, total audio bitrate and duration. The result distinguishes decimal MB/GB from binary MiB/GiB. It estimates encoded media; it does not estimate project folders, thumbnails, cache or extra copies.
How the calculation works
Payload MB = (video Mbps + audio kbps / 1,000) × seconds ÷ 8. Estimated file MB = payload MB × (1 + allowance / 100). One Mbps is 1,000,000 bits per second, and eight bits make one byte. MiB divides bytes by 1,048,576 instead of 1,000,000.
Worked example
Sixty seconds at 10 Mbps video plus 320 kbps audio produces 77.4 decimal MB before container overhead, about 73.814 MiB. A 3% allowance raises the estimate to 79.722 MB. Two files with the same duration and resolution can have very different sizes because bitrate controls this calculation.
Before using the result
Use an actual average bitrate, not only an encoder’s maximum VBR setting. Constant-quality encodes may vary widely with motion, noise and detail. Sum all audio streams. For camera recordings, measure a representative file when the recording mode’s bitrate is undocumented. Treat the allowance as a planning margin, not a measured container cost.
Keep the source values with your project notes. A number calculated from an assumed bitrate or representative sample is only as useful as that assumption. Check a real file or measured export when a deadline, upload cap or storage purchase depends on the answer.