Video file-size estimator
Estimate the video stream's approximate size from bitrate and duration before exporting or downloading; audio and container/metadata overhead can increase the finished file size.
Result
Estimated file size
How to use this tool
- 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.
- Estimates video only. Audio, codec/container details, metadata and other export overhead can add to the finished file; the effect varies by settings and content.
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
Estimated video stream size (decimal GB) = bitrate (Mbps) × duration (seconds) ÷ 8 ÷ 1000. This does not calculate the complete exported file.
Worked example
10Mbps, 30-minute video
Inputs: Video bitrate: 10 Mbps, Duration: 30 minutes
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.
Last reviewed: 2026-10-11
Assumes a constant bitrate and estimates video data only. Audio, codec/container details, metadata and variable-bitrate encoding can make the finished file differ from this estimate.
This tool provides an indicative estimate, based on the assumptions stated above.
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