RandoziVideo Bitrate Calculator
Solve for file size, video bitrate or maximum duration. Video and audio are added together, and the formulas are shown with your numbers.
File size
609.6 MB
609,600,000 bytes
(8000 + 128) kbps × 1000 × 600 s ÷ 8 = 609,600,000 bytes
How it works
- Choose what to calculate: the file size, the video bitrate, or the duration.
- Fill in the other values, or pick a video and audio preset and edit it.
- Optionally add container overhead, usually 1 to 3 percent for MP4.
- Read the result and the formula with your values. Copy the result when you are done.
What people use it for
Upload limits
Find the video bitrate that keeps a clip under an email, chat or website upload limit.
Storage planning
Estimate how many hours of footage fit on a card, a drive or a server.
Export settings
Choose a bitrate for a target size before you start a long encode.
Questions
- What is the file size formula?
- Size in bytes = (video kbps + audio kbps) × 1000 × seconds ÷ 8. Ten minutes at 8000 kbps video and 128 kbps audio is 8128 × 1000 × 600 ÷ 8 = 609.6 MB. Bits are divided by 8 to get bytes.
- How is the bitrate for a size limit found?
- Video kbps = size in bytes × 8 ÷ seconds ÷ 1000 − audio kbps. The calculator reports a problem if the audio alone is already bigger than the limit.
- Why is my real file different?
- Variable bitrate encoding, container overhead, subtitles and extra tracks change the size. This calculator uses decimal units (1 MB = 1,000,000 bytes, 1 kbps = 1,000 bits per second) and treats the bitrate as constant, so use it as a close estimate and keep a small margin.