It depends on the duration of the actual recording. We’ve prepared a setting for adjusting the quality within the project settings, adjusting the quality can increase/decrease the size of the video.
The video size will be determined by the bitrate, with a default bitrate for both the iOS and Android SDKs set at 80,000 b/s. That should generate data of an approximate size of 0.5 MB per minute. The video quality depends on the resolution used with a certain bitrate setting.
The real data size depends on many factors (how complex the UI is, how often it changes significantly) and tends to be a fraction (½ or ⅓) of the maximum size.
For more information on recording quality, frame rate, and its relation to the data size, please review our Screen Recording Quality documentation.