Name Fixed size Responsive size (resize window to see in action) Code
Default 
<button class="button is-responsive">
  Default
</button>
Small 
<button class="button is-small is-responsive">
  Small
</button>
Normal 
<button class="button is-normal is-responsive">
  Normal
</button>
Medium 
<button class="button is-medium is-responsive">
  Medium
</button>
Large 
<button class="button is-large is-responsive">
  Large
</button>