|This feature is exclusive to Java Edition.|
Sweeping Edge increases the damage dealt to mobs by each hit from a sweep attack by 50%/67%/75% of the sword's attack damage for levels I/II/III.
The formula for sweep attack damage is:
1 + Attack_Damage * (Sweeping_Edge_Level / (Sweeping_Edge_Level + 1)), rounded up/down. Here, the Attack_Damage is the sword's damage after applying Sharpness, Smite, and Bane of Arthropods. For example, an iron sword enchanted only with Sweeping Edge I deals 1 + 6 * (1 / (1 + 1)) = 4 damage to each mob hit with a sweep attack. A Diamond Sword enchanted with Sharpness V and Sweeping Edge III deals 1 + 10 * (3 / (3 + 1)) = 8 sweep damage. Any sword without Sweeping Edge deals 1 + Attack_Damage * (0 / (0 + 1)) = 1 sweep damage. Extra damage from Smite and Bane of Arthropods is applied against undead mobs and arthropod mobs, respectively.
Higher levels than Sweeping Edge III (obtainable via the use of commands or third party editors) is processed following the formula above and the sweep damage caps beneath 100% of sword's attack damage.