Video File Size & Bitrate Calculator
Two questions, one relationship. How big will this file be? and what bitrate fits under the limit? Enter what you know; the missing value is calculated.
Why two different megabytes
Bitrates are decimal — 8 Mbps means 8,000,000 bits per second. File managers usually report binary units: what Windows calls "MB" is 1,048,576 bytes. That is a 4.9% difference, and it is why a file you calculated at 600 MB shows up as 572 MB on disk. Both numbers are shown, so you can match whichever one your upload limit is using.
What this assumes
- Constant bitrate. Variable-bitrate encodes land near the average, not on it — treat the result as an estimate with a few percent of slack.
- Container overhead is small but not zero. MP4 muxing adds roughly a fraction of a percent; leave headroom if you are close to a hard limit.
- Audio is counted at the bitrate you enter. Set it to 0 for a silent or video-only file.