Box sizing value border-box will reduce the width of the content if we add padding to the content. code example

Example 1: * box-sizing border-box

*{
box-sizing: border-box;
}

Example 2: box-sizing border-box vs content-box css

box-sizing:content-box;
	"Default. The width and height properties (and min/max properties) includes only the content. Border and padding are not included"
box-sizing:border-box;	
	"The width and height properties (and min/max properties) includes content, padding and border"