Video Bitrate Calculator
Determine the exact encoding bitrate needed to hit a specific target file size for a given video duration.
Hours
Mins
Secs
Results
Video Bitrate
kbps
Total Bitrate
kbps
FFmpeg Command:
-b:v k -maxrate k -bufsize k -b:a k
Assumptions & Methodology
This calculator determines the required Average Bitrate (ABR) to achieve an exact file size.
- Conversion: Assumes 1 Kilobyte = 8192 bits (standard storage math where 1 Byte = 8 bits, and 1 KB = 1024 Bytes).
- Container Overhead: Does not explicitly calculate container overhead (e.g., MP4 MOOV atom headers), which usually adds 1-2% to the final file size. If strict limits apply (like Discord's 25MB limit), set your target slightly lower than the absolute max.
- Variable Bitrate (VBR): If using 2-pass VBR, use the resulting video bitrate as your
-b:vtarget. The encoder will distribute this average across the file.