27.29% is the change from 645 to 821
Calculation steps:
[( 821 - 645 ) ÷ 645] x 100 = 27.29%
Formula
Percentage change = [(821 - 645) / 645] x 100
Subtract the new number by the original number
821 - 645 = 176
176 ÷ 645 = 0.27286821705426356
0.27286821705426356 x 100 = 27.29%