Bootstrap/site/docs/4.1/utilities/sizing.md

---
layout: docs
title: Sizing
description: Easily make an element as wide or as tall (relative to its parent) with our width and height utilities.
group: utilities
toc: true
---

Width and height utilities are generated from the `$sizes` Sass map in `_variables.scss`. Includes support for `25%`, `50%`, `75%`, `100%`, and `auto` by default. Modify those values as you need to generate different utilities here.

{% capture example %}
<div class="w-25 p-3" style="background-color: #eee;">Width 25%</div>
<div class="w-50 p-3" style="background-color: #eee;">Width 50%</div>
<div class="w-75 p-3" style="background-color: #eee;">Width 75%</div>
<div class="w-100 p-3" style="background-color: #eee;">Width 100%</div>
<div class="w-auto p-3" style="background-color: #eee;">Width auto</div>
{% endcapture %}
{% include example.html content=example %}

{% capture example %}
<div style="height: 100px; background-color: rgba(255,0,0,0.1);">
  <div class="h-25 d-inline-block" style="width: 120px; background-color: rgba(0,0,255,.1)">Height 25%</div>
  <div class="h-50 d-inline-block" style="width: 120px; background-color: rgba(0,0,255,.1)">Height 50%</div>
  <div class="h-75 d-inline-block" style="width: 120px; background-color: rgba(0,0,255,.1)">Height 75%</div>
  <div class="h-100 d-inline-block" style="width: 120px; background-color: rgba(0,0,255,.1)">Height 100%</div>
  <div class="h-auto d-inline-block" style="width: 120px; background-color: rgba(0,0,255,.1)">Height auto</div>
</div>
{% endcapture %}
{% include example.html content=example %}

You can also use `max-width: 100%;` and `max-height: 100%;` utilities as needed.

{% capture example %}
<img class="mw-100" data-src="holder.js/100px100?text=Max-width%20%3D%20100%25" alt="Max-width 100%">
{% endcapture %}
{% include example.html content=example %}

{% capture example %}
<div style="height: 100px; background-color: rgba(255,0,0,0.1);">
  <div class="mh-100" style="width: 100px; height: 200px; background-color: rgba(0,0,255,0.1);">Max-height 100%</div>
</div>
{% endcapture %}
{% include example.html content=example %}