Digital storage · video
Video file size calculator.
Enter video and audio bitrate and the running time to see the file size in MB and GB, and how many GB each hour uses.
Inputs
File size
Enter the numbers above.
How to work out video file size from bitrate
For a constant-bitrate file, size in bytes is bitrate in bits per second times duration in seconds, divided by 8. Add the video and audio bitrates first. With kilobits meaning 1,000 bits, 1 kbps for one second is 125 bytes. Variable-bitrate files average out near their stated average bitrate, but container overhead and subtitles add a little, so treat the answer as an estimate.
Worked example. 8,000 kbps video plus 192 kbps audio is 8,192 kbps, which is 1,024,000 bytes a second. Over 2 hours (7,200 s) that is 7,372,800,000 bytes, or 7.37 GB (6.87 GiB). Each hour uses 3.69 GB, so 1 GB holds about 16 minutes. A 1,000 kbps stream for 1 minute is 7.5 MB.
Frequently asked questions
How do I calculate video file size from bitrate?
Add video and audio bitrate in kbps, multiply by seconds, multiply by 1,000 and divide by 8 to get bytes.
How many GB per hour is 5,000 kbps?
5,000 kbps is 625,000 bytes a second, which is 2.25 GB per hour.
Is the result exact?
Only for constant bitrate. Variable bitrate, container overhead and extra tracks change the real size slightly.
Is a kilobit 1,000 or 1,024 bits?
In data-rate use the SI prefix applies: 1 kbps is 1,000 bits per second. This tool uses 1,000.
Sources
Checked
- NIST, "Prefixes for binary multiples", opened 15 October 2026. kibi, mebi, gibi, tebi are 2^10, 2^20, 2^30, 2^40; under SI mega means 1,000,000, so 1 MB = 10^6 bytes and 1 GB = 10^9 bytes
Runs entirely in your browser. Nothing you type is sent or stored.
Scope
Estimate for a constant bitrate. Encoders, containers and variable bitrate shift the real file size.