Video File Size Calculator
Estimate a video file’s size from its bitrate and duration, with size comparisons for common quality presets.
How it works
size (MB) = bitrate (Mbps) × 60 × minutes ÷ 8
Bitrate is how much data each second of video consumes, quoted in megaBITS per second — divide by 8 for megabytes. Multiply by the duration in seconds and you have the file size, regardless of resolution: a heavily compressed 4K file can be smaller than a lightly compressed 1080p one. Resolution presets here reflect typical streaming-grade bitrates; production and camera bitrates run far higher.
Worked example
A 60-minute video at 8 Mbps: 8 × 60 × 60 ÷ 8 = 3,600 MB — 3.60 GB. The same hour at a 45 Mbps 4K bitrate would take 20.25 GB.
Frequently asked questions
Why is my camera footage so much bigger than this?
Cameras record at high bitrates to preserve editing quality — 100+ Mbps for 4K is normal, versus ~45 Mbps for streaming-grade delivery. An hour of 100 Mbps footage is 45 GB; the export you upload gets compressed far smaller.
Does resolution change the file size?
Only through the bitrate you choose. Size = bitrate × time, full stop — higher resolutions just need more bitrate to look clean. As a rule of thumb: 720p ~5 Mbps, 1080p ~8, 1440p ~16, 4K ~35–55 for streaming-quality encodes.
Is audio included in the estimate?
The formula covers whatever bitrate you enter. If your figure is video-only, add the audio: a 128 kbps stereo track adds about 0.96 MB per minute, so roughly 58 MB per hour.
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This calculator is for educational purposes. Double-check important results before acting on them.