Video File Size & Bitrate Calculator
File size is duration times bitrate, and that one rule solves most export problems. This free calculator works both ways: it estimates the size of a video from its bitrates, or finds the bitrate that lands under a target such as a 25 MB Discord limit, and suggests a sane bitrate for your resolution, frame rate and codec.
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How to use it
Pick a mode: file size from bitrates, bitrate for a target size, or a recommended bitrate.
Enter the length of the video and the bitrates or the target size.
Read the result, then set your export bitrate to the figure shown.
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This tool gives you the starting point. Market4Me writes, storyboards and makes the video, and shows the price before anything renders.
Make my first video →Frequently asked questions
How do I calculate video file size?
Multiply the total bitrate (video plus audio, in kilobits per second) by the duration in seconds, then divide by 8 to get kilobytes. The calculator does this for you and shows megabytes.
Why does the bitrate for a target size leave a little room?
Containers such as MP4 and MOV add a small overhead, so the calculator reserves about 2% of the target before it works out the bitrate.
What bitrate should I use for 1080p?
For 1080p at 30 fps, H.264 usually looks good around 6 to 8 Mbps. H.265 and AV1 reach similar quality at lower bitrates. The recommendation here is a starting point, so check the result on a real clip.