What does Video Bitrate Calculator do?
Find the average video bitrate needed for a target file size. Enter duration, target MB or GB, and an audio bitrate; Tubelexity divides available bits by time and subtracts audio bitrate. The calculator rejects impossible targets where audio alone exceeds the allowance. Real encoders may miss the exact size because of variable bitrate and container overhead.
How to use Video Bitrate Calculator
- 1Enter duration as seconds, MM:SS or HH:MM:SS.
- 2Enter a target size in MB or GB.
- 3Reserve audio bitrate, or choose zero for silent video.
- 4Read the required video bitrate in kbps and Mbps.
Supported inputs and outputs
Inputs
Duration, Target MB or GB, Audio bitrate
Outputs
Required video bitrate, Total bitrate, Estimated size
Practical uses
- Planning an export under a size limit
- Choosing a target bitrate before encoding
- Comparing video and audio allocation
Browser and media limitations
- The result is an average, not a promise of exact output size.
- Variable bitrate and container overhead are not predicted.
- The tool does not encode or inspect video.
How local processing works
The formula runs in browser JavaScript. No file, FFmpeg or upload is required.
Frequently asked questions
How do I calculate video bitrate for a target size?
Convert target bytes to bits, divide by duration and subtract audio bitrate to estimate available video bitrate.
Why is my target impossible?
The selected audio bitrate alone would exceed the target size for that duration.
Does the calculator include audio?
Yes. It reserves the selected audio bitrate before reporting video bitrate.
Will the exported video hit the target exactly?
No. Encoder rate control and container overhead can change the final size.