How to calculate margins as a percentage?

Question

css

Good day!
I have a 960px wide layout with 10px side padding to convert these margins to percentages I divide by 10px/940px*100 but the margins are 14px and the blocks don't match the layout. Everywhere it is written that it is necessary to calculate exactly this way. Who can tell what is the problem?

Answer 1

960px = 100%
1px =100/960= 0.10416%
And now we calculate:
940px = 0.10416%*940px=97.916%
10px = 0.10416%*10px = 1.0416%
jsfiddle.net/jnrt7v12

Answer 2

Do you want to know the padding width in %?
960 -> 100%
10 -> x
x*960 = 10*100
x= 10/960*100
Two for you :-P

Answer 3

give up fixed sizes and px