1em how much px

Currently, absolute units must work correctly only on printed output and on high-resolution devices. CSS considers that printers, unlike screens, do not need to have different sizes for px in order to print sharp lines.

In print media, a px thus not only has the same visual appearance from one device to another, but indeed it is measurably the same. Use em or px for font sizes CSS inherited the units pt point and pc pica from typography.

Printers have traditionally used those and similar units in preference to cm or in. In CSS there is no reason to use pt , use whichever unit you prefer. But there is a good reason to use neither pt nor any other absolute unit and only use em and px. Here are a few lines of different thickness. Although points can be used on screen, they are the standard in printing because they are a factor of DPI.

Percent and EMs on the other hand are relative measurements. The size of an EM or percentage unit depends on its parent. Note: 16px is used as the body text size in all conversions because that is the browser default. You will change 16px to your base text size. Style sheets become easier to maintain because all text set in EMs scale to the body font-size.

Choosing this unit will result in a perfectly sharp and visible font on the screen, regardless what kind of display you will use. The only drawback is that fonts expressed in this units cannot scale but it is possible to use the zoom feature of web browsers to enlarge the text. Ems em are scalable units, used in digital media.

Ems are a popular unit because they are easy to understand, can be scaled if desired, and are mobile-device friendly. The main drawback of ems is the threat of cascading - because this unit is relative, changing the height of the "parent" text immediately resizes all other fonts.

Points pt are a unit for print CSS only. Points are not scalable and should be avoided in digital media. This unit is perfectly scalable, allows for zooming in and out. Ask Question. Asked 10 years, 11 months ago. Active 3 years, 3 months ago. Viewed 70k times. Improve this question. TylerH Add a comment. Active Oldest Votes. As one of the links states: the "em" value is based on the width of the uppercase M So it's going to be different for every font.

I'm going to make some test pages and see for myself. Improve this answer. Is there some source where i can read around it. But now that I read it, that page also says "Em is traditionally defined as the width of the uppercase M in the current face and point size. It is more properly defined as simply the current point size.

For example, in point type, em is a distance of 12 points. Read this: v1. Basically 1em equals the inherited font-size on the current element. You can set font-size for your body element, and have all other elements use 'em' in their font-size and it will be relative to the size you set in the body.

This is a nice way to make your fonts responsive all you need to do is to change the size for your body once Here are the salient points. Without ancestor magnification, 1em is exactly equal to the pixel font-size attribute. Warning A major caveat to 2 is that the relative ratio of the ex unit is wildly unstable.