Visit the Minecraft Wiki for basic information about Efficiency

Efficiency is an enchantment added by vanilla Minecraft. Efficiency can come in five tiers, each increasing the tool speed by 30% from the previous rank. The speed bonus applies to all blocks, regardless if the tool is appropriate or not, meaning an axe can gain break pickaxe tool blocks at 130% speed with Efficiency I.

Tier Speed
I 130%
II 169%
III 220%
IV 286%
V 371%