Answers for "bootstrap button size"

bootstrap buttons Sizes

Fancy larger or smaller buttons? Add .btn-lg or .btn-sm for additional sizes.
<button type="button" class="btn btn-primary btn-lg">Large button</button>
<button type="button" class="btn btn-secondary btn-lg">Large button</button>

<button type="button" class="btn btn-primary btn-sm">Small button</button>
<button type="button" class="btn btn-secondary btn-sm">Small button</button>

<button type="button" class="btn btn-primary btn-lg btn-block">Block level button</button>
<button type="button" class="btn btn-secondary btn-lg btn-block">Block level button</button>

<a href="#" class="btn btn-primary btn-lg active" role="button" aria-pressed="true">Primary link</a>
<a href="#" class="btn btn-secondary btn-lg active" role="button" aria-pressed="true">Link</a>

full width bootstrap button

class="btn btn-primary btn-block"

bootstrap 4 button size

<button type="button" class="btn btn-primary btn-lg">Large button</button>
<button type="button" class="btn btn-secondary btn-sm">Small button</button>