Relative to the parent
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.
Width 25%
Width 50%
Width 75%
Width 100%
Width auto
<div class="w-25 p-3 bg-dark text-white">Width 25%</div>
<div class="w-50 p-3 bg-dark text-white">Width 50%</div>
<div class="w-75 p-3 bg-dark text-white">Width 75%</div>
<div class="w-100 p-3 bg-dark text-white">Width 100%</div>
<div class="w-auto p-3 bg-dark text-white">Width auto</div>Height 25%
Height 50%
Height 75%
Height 100%
Height auto
<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>You can also use max-width: 100%; and max-height: 100%; utilities as needed.
<svg class="bd-placeholder-img mw-100" width="100%" height="100"
aria-label="Placeholder: Max-width 100%"
preserveAspectRatio="xMidYMid slice" role="img" focusable="false"><title>Placeholder</title><rect width="100%" height="100%" fill="#333" /><text x="50%" y="50%" fill="#eee" dy=".3em">Max-width 100%</text></svg>Max-height 100%
<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>Relative to the Viewport
You can also use utilities to set the width and height relative to the viewport.
<div class="min-vw-100">Min-width 100vw</div>
<div class="min-vh-100">Min-height 100vh</div>
<div class="vw-100">Width 100vw</div>
<div class="vh-100">Height 100vh</div>