Bootstrap class: .form-control-lg

<input class="form-control form-control-lg" type="text" placeholder=".form-control-lg">

Preview

Sass source

/* _forms.scss:149 */
.form-control-lg {
  height: $input-height-lg;
  padding: $input-padding-y-lg $input-padding-x-lg;
  font-size: $font-size-lg;
  line-height: $input-line-height-lg;
  @include border-radius($input-border-radius-lg);
}

Uses variables

/* _forms.scss:149 */
$input-height-lg
$input-padding-y-lg
$input-padding-x-lg
$font-size-lg
$input-line-height-lg
$input-border-radius-lg