Answers for "center class in bootstrap"

centralize div bootstrap

<div class="row align-items-center justify-content-center">
    <div class="col">This will be centered vertically and horizontally</div>
</div>

bootstrap 4 center div

<div class="d-flex justify-content-start">...</div>
<div class="d-flex justify-content-end">...</div>
<div class="d-flex justify-content-center">...</div>
<div class="d-flex justify-content-between">...</div>
<div class="d-flex justify-content-around">...</div>

bootstrap center

<div class="row h-100">
   <div class="col-sm-12 my-auto">
     <div class="card card-block w-25">Card</div>
   </div>
</div>