Why Calculate Width Calculating the pixel width of a web page is for the neatness and compatibility of CSS web page layout. It is common for us to calculate the width of the entire page when we lay out the left and right structural web pages or use padding and margin layout. If we do not calculate the width, whether the width is too large or too small, misalignment problems will occur. How to calculate CSS width Example 1: We calculate the layout style of a left and right structure. If the total width is 400px, then the sum of the left and right should be less than 400px, then we may have 300px on the left and 100px on the right. Correct code:
