This calculator runs in your browser. It does not upload or inspect your video; it estimates the result from the settings you enter.
How the estimate works
Approximate bytes = (video bitrate + audio bitrate) × duration in seconds ÷ 8. A bitrate of 8 Mb/s means roughly one megabyte of video data each second before container overhead; a 10-minute recording at that rate is around 600 MB plus audio and overhead.
The result is intentionally approximate. Variable bitrate encoding changes the average bitrate from scene to scene. Codec, frame rate, resolution, and how much the screen changes influence the bitrate required for acceptable quality.
Example: a narrated screen walkthrough
Use the number to plan a transfer, not as a promise of the final encoded size. An export preset with a different average bitrate can make the real file much smaller or larger.
| Setting | Example value |
|---|---|
| Duration | 10 minutes |
| Video bitrate | 8 Mb/s |
| Audio bitrate | 0.128 Mb/s (128 kb/s) |
| Estimated size | About 610 MB, before overhead |
How to make a recording smaller
For text-heavy product demos, test whether small interface labels remain readable after compression. A smaller file is not useful if the viewer cannot follow the tutorial.
- Trim dead time before export: less duration means less data.
- Choose a suitable export resolution for the destination instead of automatically choosing 4K.
- Use an efficient codec supported by your viewers and test visual quality at the chosen bitrate.
- Reduce frame rate only when the motion of the recording still looks clear.
Common questions
Is the file size estimate exact?
No. It is an estimate from average video and audio bitrates. Variable bitrate, container overhead, codec settings, and scene complexity change the final file size.
Does 4K always mean a larger recording?
Not by itself. File size depends mainly on encoded bitrate and duration. Resolution, frame rate, codec, and content influence the bitrate needed for acceptable quality.
Explore the Mac recorder preview
Mac Screen Recorder is in development. See the planned editor and check the homepage for download availability.
See the product preview →