Formula
Size (bytes) = (video bitrate + audio bitrate) × seconds ÷ 8. Bitrates are in bits per second and files in bytes, and one byte has 8 bits.
Examples
Ten minutes at 8 Mbps of video plus 128 kbps of audio make about 609.6 MB.
To fit a one-minute clip into 100 MB, use about 12.81 Mbps of video with 128 kbps of audio, already with a 3% safety margin.
Good to know
- With variable bitrate (VBR), the real size can differ a little from the estimate.
- Recording at a higher bitrate than the upload service uses does not help: it will compress the video again.
To see how long the upload or download takes, use the download time calculator.
Frequently asked questions
How many GB is one hour of 1080p video?
At 8 Mbps of video, about 3.7 GB per hour. Phone recordings often use 15 to 20 Mbps, so 7 to 9 GB per hour.
Why does the file come out bigger?
The container (MP4, MKV) and extra tracks add a little. That is why the bitrate result keeps a 3% margin.
See also
Results are estimates for information only and are not financial, legal or medical advice. Rates, taxes and fees vary — confirm with a professional or your lender.