Bitrate calculator
Work out the bitrate needed to hit a target file size for a given duration — useful when exporting to fit a specific size limit (e.g. an upload cap).
Result
Required bitrate
How to use this calculator
- Enter your target file size.
- Enter the video or audio's duration.
- Read the bitrate to use in your export settings.
Assumptions
- Assumes the export uses a constant bitrate — a variable-bitrate export may end up somewhat above or below the target size.
Technical details: what the fields mean
- Target file size
fileSizeMb - The file size you're aiming for.
- Duration
durationMinutes - Length of the video or audio.
Methodology
Bitrate (Mbps) = file size (MB) × 8 ÷ duration (seconds) — the inverse of the video/audio file-size estimators.
Worked example
100MB target, 5-minute video
Inputs: fileSizeMb=100, durationMinutes=5
Result: 2.67 Mbps
Practical guidance
- Aim slightly under your actual size limit, since container/format overhead and variable-bitrate encoding can push the real file a little above a constant-bitrate calculation.
Common mistakes
- Setting the exact calculated bitrate with no margin, then finding the exported file is slightly over the target due to format overhead or a variable-bitrate encoder.
FAQs
What bitrate do I need for a 100MB, 5-minute video?
About 2.67Mbps — enter your own target size and duration above for an exact figure.