SizeCap

SizeCap, for iPhone and iPad, compresses a video to a size limit you enter in MB. It works out the bitrate from your number, exports, then reads the actual file size. If the result is over, it re-encodes once with a corrected bitrate; if that still misses, it asks for a larger cap. If the cap is too small for the clip's length, the app shows the minimum size that would work. HEVC two-pass is the default, with H.264 as a compatibility option. Compression runs on the device, and the app has no networking code of its own. Single videos are free; a one-time Pro purchase adds batches of up to 50.