Video file-size estimator
Estimate a video file's size before exporting or downloading it, from its bitrate and duration.
Result
Estimated file size
How to use this calculator
- Enter the video's bitrate — check your export settings, or use a typical value (5Mbps for standard HD, 10–25Mbps for higher quality).
- Enter the video's duration in minutes.
- Read the estimated file size.
Assumptions
- Assumes a constant bitrate throughout — variable-bitrate encoding (common for streaming/export) will give a somewhat different actual size.
- Video only — doesn't add audio track size, which is usually small by comparison.
Technical details: what the fields mean
- Video bitrate
bitrateMbps - Video bitrate — how much data is used per second of video. Higher bitrate means better quality and a larger file.
- Duration
durationMinutes - Total length of the video.
Methodology
File size (MB) = bitrate (Mbps) × duration (seconds) ÷ 8. Converted to GB by dividing by 1000.
Worked example
10Mbps, 30-minute video
Inputs: bitrateMbps=10, durationMinutes=30
Result: 2.25 GB
Practical guidance
- Check your camera or editing software's export settings for the actual bitrate used, rather than guessing — this varies a lot by resolution and quality preset.
Common mistakes
- Confusing video resolution (e.g. 1080p, 4K) with bitrate — the same resolution can be encoded at very different bitrates and file sizes.
FAQs
How big will a 30-minute 10Mbps video be?
About 2.25GB — enter your own bitrate and duration above for an exact estimate.