How this calculator works
The overhead percentage reserves part of the total size budget before audio is subtracted. Encoders may miss a size target with variable bitrate, multiple audio tracks or metadata; this estimate does not predict visual quality.
The formula
Total kbps = target bytes × 8 / duration seconds / 1000. Video kbps = total kbps × (1 − overhead/100) − audio kbps.A quick example
A 1 GB target over 10 minutes allows 13,333.33 kbps total. With 128 kbps audio and no overhead, 13,205.33 kbps remains for video.
How to use this calculator
- Choose the settings that match your scenario, using the units shown beside each field.
- Enter file size, file size unit, video duration (minutes), audio bitrate (kbps).
- Calculate, then review the method and assumptions alongside the results.
A few common questions
What if the audio alone exceeds the file budget?
Increase the target size, reduce audio bitrate or shorten the duration; a negative video budget is rejected.
Does the result tell me the best codec?
No. Codec choice, resolution, motion and encoder settings affect quality independently of this size budget.