A system and method efficiently calculates an estimated amount of storage required to split a clone volume from its parent volume. The system and method is illustratively embodied as a command line interface (CLI) command, i.e., a clone split estimate command, executed by an estimation module of a storage system. Notably, the estimation module cooperates with a file system of the storage system to quickly access data structures containing information used to perform the storage calculation without the need to access each block of the clone and parent volumes.