How to use this calculator
Work backwards from file size and duration to estimate average bitrate, or estimate size from a target bitrate.
How the calculation works
- Choose a calculation mode.
- Enter file size, duration, or bitrate.
- The result uses transparent bits-per-second math.
Formula
Bitrate kbps = file size bytes x 8 / duration seconds / 1000.
Example
A 5 MB file that runs 3 minutes has an average bitrate near 233 kbps.
Understanding your result
Use the output as a practical starting point, then review it before using it in an important workflow.
Assumptions and limitations
- Variable bitrate audio may not match one exact constant rate.
- Use this as planning math, not a codec inspection tool.
Frequently asked questions
Does this require an account?
No. The core tool works without creating a Tool2Do account.
Is my input included in share links or analytics?
No. Tool2Do share actions use the tool page URL and safe metadata, not private values or uploaded files.