<percentage>

The <percentage> CSS data types represent a percentage value. Many CSS properties can take percentage values, often to define sizes in terms of parent objects. Percentages are formed by a <number> immediately followed by the percentage sign %. Just as is the case with all other units in CSS, there isn't a space between the '%' and the number.

Many length properties use percentages, such as width, margin and padding. Percentages can also be seen in font-size, where the size of the text is directly related to the size of its parent.

Note: only calculated values are inherited. So, even if a percentage value is used on the parent property, a real value, like a width in pixel for a <length> value, will be accessible on the inherited property, not the percentage value.

Interpolation

Values of the <percentage> CSS data type can be interpolated in order to allow animations. In that case they are interpolated as real, floating-point numbers. The speed of the interpolation is determined by the timing function associated with the animation.

Examples

Width and margin-left

<div style="background-color:#0000FF;"> 
  <div style="width:50%;margin-left:20%;background-color:#00FF00;">
    Width: 50%, Left margin: 20%
  </div> 
  <div style="width:30%;margin-left:60%;background-color:#FF0000;">
    Width: 30%, Left margin: 60%
  </div> 
</div>

The above HTML will output:

Font-size

<div style="font-size:18px;">
  <p>Full size text (18px)</p>
  <p><span style="font-size:50%;">50%</span></p>
  <p><span style="font-size:200%;">200%</span></p>
</div>