Traditionally, Parsvanath (Pārshvanātha) is the 23rd Tirthankara and Mahavira is the 24th. In Jain scripture and tradition, Mahavira is said to have lived about 273 years after Parsvanath. So, the gap is 273 years. This sequence is shared by the Śvetāmbara and Digambara traditions, though exact dates and details can vary slightly in different texts. You can read more here