I had loaded up some video in my video converter and then i set the setting to convert them into 4K. It show what the size is of the video, but how or can i load up all the videos and it give me the total size of all the videos.
Is this in Shotcut, or is this a different product?
Are you wanting to know the size of the converted files before they are converted?
This could be estimated somewhat close with Constant Bitrate mode, but that is usually not the best mode in terms of the quality/size tradeoff. Guaranteeing high quality requires using a high bitrate that makes very large files. Meanwhile, Variable Bitrate mode can create significantly smaller files at equally high quality, but the final size is hard to predict until the conversion is complete. The final size depends greatly on the type of video being converted (static vs action, for instance).