S: 41″ without Buckle 42″ With Buckle 37″ Buckle to First Hole. M: 44″ without Buckle 45″ With Buckle 42″ Buckle to First Hole. L: 46″ without Buckle 47″ With Buckle 43″ Buckle to First Hole. XL: 48″ without Buckle 49″ With Buckle 45″ Buckle to First Hole.