What does Video File Size Calculator do?
Estimate how large a video file may be before export. Enter duration and average video and audio bitrates; Tubelexity multiplies combined bitrate by time and converts bits to bytes. The calculator splits video and audio portions so you can see which setting matters most. Results are estimates because variable bitrate and container overhead can change the final file.
How to use Video File Size Calculator
- 1Enter duration as seconds, MM:SS or HH:MM:SS.
- 2Enter video bitrate in kbps or Mbps and audio bitrate in kbps.
- 3Read the estimated video, audio and total sizes.
- 4Adjust values or open the reverse bitrate calculator.
Supported inputs and outputs
Inputs
Duration, Video bitrate, Audio bitrate
Outputs
Estimated KB, MB or GB, Video and audio portions
Practical uses
- Planning an upload size
- Comparing export bitrates
- Estimating storage for recordings
Browser and media limitations
- Presets are examples, not universal recommendations.
- Variable bitrate and container overhead can alter real file size.
- This calculator does not inspect or encode video.
How local processing works
The calculation runs in browser JavaScript. No file, FFmpeg or network upload is needed.
Frequently asked questions
How do I calculate video file size?
Multiply average video plus audio bitrate by duration, then divide bits by eight to estimate bytes.
Does audio bitrate affect file size?
Yes. Audio contributes its bitrate for the full duration, so multiple tracks would add more.
Why is my export a different size?
Variable bitrate, metadata and container overhead make this a planning estimate.
Are 1080p preset bitrates exact?
No. Presets are examples; frame rate, content and codec all matter.