Whereas it's appropriate to use 'cm', or 'in' when specifying measures relative to the screen or page context. Pixel is a static measurement, while percent and EM are relative measurements. In contemporary typography, an em is equal to the point-size of a font.
So, 1em is how many pixels, when you bring your arms and legs in, you increase your ending omega by decreasing you ending inertia. In traditional printing, 'em' referred to the with including serifs of the uppercase letter 'M' for a given type face. Pixels are used on screens because screens are measured in pixels. First you need to export the data. There's no one right answer to this question. The size of an EM or percent depends on its parent. What is the text sizing difference between PX, EM, PT.