Video File Size Calculator
Know the upload size before the export finishes.
Video File Size Calculator
Bytes = seconds x (video Mbps x 1,000,000 + audio kbps x 1,000) / 8; MB = bytes / 1,000,000.
Calculated instantly
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What This Calculator Does
The Video File Size Calculator estimates how large a video export will be from its duration, video bitrate, and audio bitrate. It reports decimal MB and GB for upload limits and binary GiB for the size some operating systems display.
How It Works
Video and audio bitrates are converted to bits per second, added, and multiplied by the duration in seconds to get total bits. Dividing by 8 converts to bytes, and dividing by one million or one billion gives decimal megabytes or gigabytes. The GiB result divides by 1,073,741,824, the binary definition. Size per minute applies the same calculation to 60 seconds.
Example
A 10 minute clip at 12 Mbps video and 192 kbps audio uses 12,192,000 bits per second. Over 600 seconds that is 7,315,200,000 bits, or 914,400,000 bytes. That is about 914 MB, 0.914 GB, or 0.852 GiB, and about 91 MB per minute.
Formula
seconds x (video bps + audio bps)total bits / 8bytes / 1,000,000bytes / 1,073,741,824Reading the Results
Estimated file size
A constant-bitrate estimate in decimal megabytes. Variable bitrate and container overhead can move the real file by several percent.
Estimated size in GB
The same estimate in decimal gigabytes, the unit used by upload forms and drive marketing. Compare it with the platform limit before exporting.
Estimated size in GiB
The binary unit reported by some file managers. It is numerically smaller than the decimal GB figure for the same file.
Sources and References
YouTube Help - Recommended upload encoding settings
Bitrate and resolution guidance
Platform guidance on bitrates for common resolutions and frame rates.
Apple Support - About storage capacity
Decimal versus binary storage units
Explains why a drive quoted in decimal GB shows less in a binary GiB display.
References identify the method or data behind this calculator. Where a standard or tariff changes, the current edition applies, and the assumptions stated above take precedence over a remembered figure.
Frequently Asked Questions
Why is the estimated size different from the exported file?
Most encoders use variable bitrate, so the actual data rate changes with scene complexity. Container overhead, chapter markers, subtitles, and a second audio track also add bytes. Treat the estimate as a planning figure and check the real file before uploading.
Does a higher bitrate always mean better quality?
Up to a point. Beyond the level the codec and source can use, extra bitrate adds file size without visible improvement. Resolution, frame rate, codec efficiency, and the quality of the source matter as much as the number.
What is the difference between MB and MiB?
MB is decimal, one million bytes. MiB is binary, 1,048,576 bytes. The same file is a smaller number in MiB, which is why a 1 GB drive appears as about 0.93 GiB in some operating systems. This calculator shows both so the units are not confused.
How do I hit an upload limit?
Calculate the allowed bitrate by rearranging the formula: total bits per second = target bytes x 8 / seconds. Subtract the audio bitrate, then set the video bitrate below that. Leave a margin for container overhead, because the limit applies to the whole file.
Does audio bitrate matter for file size?
It is small compared with video but not zero. At 192 kbps, a 10 minute clip adds about 14.4 MB. For a long recording or a high video bitrate the audio share shrinks, but it still counts against a tight upload limit.