Although Guillotine specifies a hit accuracy of 30%, the chance of hitting a Pokémon is calculated using a formula.
The accuracy starts at 30% when the Pokémon have the same level, and is 1% more likely to hit for every level the user is higher than the target. If the user is at least 70 levels higher than the target, Guillotine will always hit. If the user is a lower level than the target, the move always fails.
This chance of hitting is not an accuracy: it is not affected by accuracy and evasion stats, nor is it affected by other accuracy modifiers such as Gravity, Wide Lens, and Compound Eyes. Additionally, Guillotine cannot hit a semi-invulnerable Pokémon. However, effects that guarantee moves to hit (such as No Guard and Lock on) still affect Guillotine. Pokemon with the Sturdy Ability are immune.
Z-Move Base Power: 100