97.25% is the change from 255 to 503
Calculation steps:
[( 503 - 255 ) ÷ 255] x 100 = 97.25%
Formula
Percentage change = [(503 - 255) / 255] x 100
Subtract the new number by the original number
503 - 255 = 248
248 ÷ 255 = 0.9725490196078431
0.9725490196078431 x 100 = 97.25%