The formula for damage reduction by explosions is
(8 × level)%, meaning that for every additional Level another 8% of the damage is absorbed. The highest level (Blast Protection IV) will absorb 32% (
4 x 8%) of the damage inflicted by any explosion. Theoretically at level 13 no damage from explosions is possible (because it should absorb 100%), but the damage reduction is capped at 80%. Blast Protection also reduces explosion knockback by
(15 × level)%.
Protection, Blast Protection, Fire Protection, and Projectile Protection are mutually exclusive.[Bedrock and Legacy Console editions only] However, if commands are used to have two or more of these enchantments on the same item, the effects will stack.