As we clearly know that font-size property in out css stylesheet is one of the most consfusing aspects for text scaling. The beginers in web development mostly seems eager to know the difference in the units of font-size. We very well know these four units of font-size is best suited for the web.But which one is most preferable to use. So let’s come here to know about something on this topic- The differences of font-size’s units.
1. “Ems” (em): The “em” is a scalable unit that is used in web document media. An em is equal to the current font-size, for instance, if the font-size of the document is 12pt, 1em is equal to 12pt. Ems are scalable in nature, so 2em would equal 24pt, .5em would equal 6pt, etc. Ems are becoming increasingly popular in web documents due to scalability and their mobile-device-friendly nature.
2. Pixels (px): Pixels are fixed-size units that are used in screen media (i.e. to be read on the computer screen). One pixel is equal to one dot on the computer screen (the smallest division of your screen’s resolution). Many web designers use pixel units in web documents in order to produce a pixel-perfect representation of their site as it is rendered in the browser. One problem with the pixel unit is that it does not scale upward for visually-impaired readers or downward to fit mobile devices.
3. Points (pt): Points are traditionally used in print media (anything that is to be printed on paper, etc.). One point is equal to 1/72 of an inch. Points are much like pixels, in that they are fixed-size units and cannot scale in size.
4. Percent (%): The percent unit is much like the “em” unit, save for a few fundamental differences. First and foremost, the current font-size is equal to 100% (i.e. 12pt = 100%). While using the percent unit, your text remains fully scalable for mobile devices and for accessibility.
So here we come to know the differences among four ie: 1em = 12pt = 16px = 100% and the ratio b/w pt:px = 3:4.
Now let’s something on Em and Percent, that what we should chose if both are almost similar, but really there is a slightly difference while applying in application. If you change your base font-size from percent to ems (i.e. body { font-size: 1em; }), you probably won’t notice a difference. Let’s see what happens when “1em” is our body font-size, and when the client alters the “Text Size” setting of their browser (this is available in some browsers, such as Internet Explorer).
Well, both are prefereble but em is looking much than percent in now days website development.
Pixels are now considered acceptable font size units (users can use the browser’s “zoom” feature to read smaller text), although they are starting to cause some issues as a result of mobile devices with very high density screens (some Android and iPhone devices have upwards of 200 to 300 pixels per inch, making your 11- and 12-pixel fonts very difficult to see!).