Just to clear something up, it would be a 1/16 chance, not 1% as the calculator states
Provided the battle isn't rigged to always use minimum damage, the current damage value D is altered using a random number 0 ≤ R ≤ 15:
D' = (D * (100-R)) ÷ 100
This basically means there are 16 possible damage outcomes. Source.