This video file size calculator estimates how large a video file will be from its duration and its video + audio bitrate. It is handy for planning storage, picking an export setting, or checking whether a clip will slip under an upload or email limit before you spend time encoding it.
How it works
File size is governed entirely by bitrate and length — resolution and codec only matter because they determine the bitrate. The tool:
- Converts the duration to seconds:
hours×3600 + minutes×60 + seconds. - Adds the video and audio bitrates into one total kbps.
- Computes bytes as
total_kbps × 1000 × seconds ÷ 8(×1000 to go from kilobits to bits, ÷8 to go from bits to bytes). - Shows the result in the most readable unit, stepping up through B, KB, MB, GB and TB in 1024-based steps.
Example
A 10-minute clip at 5000 kbps video plus 192 kbps audio:
- total bitrate =
5000 + 192 = 5192 kbps - bits =
5192 × 1000 × 600 = 3,115,200,000 - bytes =
÷ 8 = 389,400,000≈ 371 MB
| Video | Audio | Duration | Estimated size |
|---|---|---|---|
| 5000 kbps | 192 kbps | 10 min | ~371 MB |
| 8000 kbps | 256 kbps | 5 min | ~295 MB |
| 2500 kbps | 128 kbps | 60 min | ~1.10 GB |
Enter your numbers and the size updates instantly — everything stays in your browser, nothing is uploaded.