When paralyzed, pokemon speed is reduced. But, how much by?
Its speed will be 25% of its maximum. It also give it a 25% chance to be not able to move.
Depends on the generation.
Gen I-VI: Reduced by 75%, to become 25% of original speed. Generation-specific mechanics apply. Gen VII-Present: Reduced by 50%, to become 50% of original speed. Generation-specific mechanics apply.
More information can be found here.
Hope I helped!
It is 25% of the original.
I am think it is cut in half. Terribly sorry if this is wrong.