Production & signals
Bitrate from File Size Calculator
Derive average bitrate from a binary file size and duration.
Use this to inspect a rendered file's average bitrate before delivery.
What the result means
This reverses the binary-size estimate and reports megabits per second; variable bitrate files have an average here.
The formula
File size MiB * 8 * 1,048,576 / duration seconds / 1,000,000
Results are displayed to at most two decimal places. Calculations use the unrounded inputs.
A worked example
Put the formula to work
- File size (MiB)
- 71.53
- Duration (seconds)
- 60
Average bitrate (Mbps): 10
About 71.53 MiB over 60 seconds is approximately 10 Mbps.
How to use this calculator
- Read the binary file size.
- Measure exact duration.
- Convert bytes to bits and divide by seconds.
- Treat the result as an average.
Why this number matters
Reverse planning helps compare a delivered file with an encoder's intended bitrate.
Input definitions
- File size (MiB)
- Binary mebibytes of the file.
- Duration (seconds)
- Duration in seconds; must be greater than zero.
Assumptions and limitations
- Container and audio streams are included in the observed size.
- Variable bitrate changes moment-to-moment rate.
- No codec quality claim is made.
Methodology
The default result and worked example use the same calculation functions as the interactive tool. The formula cannot verify the quality or scope of your source data.
Read our calculation methodology
Last updated .