Video File Size & Bitrate Calculator
Find the bitrate that fits a size limit, or estimate how big a video will be. Everything runs in your browser; nothing is uploaded.
Video bitrate that fits
3.26 Mbps
3256 kbps video + 128 kbps audio, with 5% headroom for 20 MB.
- H.265: up to about 1080p should look fine.
- H.264: up to about 1080p should look fine.
How the calculator works
A video file is basically its bitrate multiplied by its duration. Bitrate is measured in bits per second and file size in bytes, and one byte is 8 bits, so:
size (MB) = (video Mbps + audio Mbps) x seconds / 8In Fit a size limit mode the calculator runs the formula backwards: it converts the limit to megabits, divides by the duration, subtracts the audio, and keeps 5% in reserve for container overhead and encoder inaccuracy. The resolution hint compares the result with rough minimum bitrates for watchable everyday footage at 30 fps. Fast motion, grain, and 60 fps footage need more.
Typical bitrates for reference
| Content | H.264 | H.265 |
|---|---|---|
| 720p screen recording | 1 to 2 Mbps | 0.6 to 1.2 Mbps |
| 1080p talking head | 5 to 8 Mbps | 3 to 5 Mbps |
| 1080p sports or games, 60 fps | 10 to 15 Mbps | 6 to 10 Mbps |
| 4K phone video, 30 fps | 35 to 50 Mbps | 20 to 30 Mbps |
What to do with the result
- If the bitrate is comfortable for your resolution, compress the video and check the size.
- If it is too low, trim the clip first. Halving the duration doubles the bitrate you can use.
- If trimming is not an option, lower the resolution or share a cloud link instead.
The BoltCompress compressor shows an estimated output size for each level before you start, so you can pick the lightest one that fits. For the full explanation, read how to calculate video file size and check current app limits on the upload limits page.