[html] How can I increase the size of a bootstrap button?

For example I've made my button

<div class="btn btn-default">
  Active
</div>

and it looks like the following

However I would like to have my button like this

How can I enlarge the width of the bootstrap button regardless of text size?

Use block level buttons, those that span the full width of a parent You can achieve this by adding btn-block class your button element.

Documentation here

You can add your own css property for button size as follows:

.btn {
    min-width: 250px;
}

Just simply add to the class of the bootstrap code.

.login
{
width: 20%;
margin-top: 39.5%;
margin-left: 35%;
}

<button type="button" class="btn btn-outline-dark btn-lg login">Login</button> 

bootstrap comes with clas btn-lg http://getbootstrap.com/components/#btn-dropdowns-sizing

<div class="btn btn-default btn-block">
  Active
</div>

but if you want to have the button of the width of your column / container add btn-block

<div class="btn btn-default btn-lg">
      Active
    </div>

However this will expand to 100% so make surt ethat you will wrap your button in certain amount of columns e.g. then you know its always stays 3 columns until xs screen

<div class="col-sm-3">
             <div class="btn btn-default btn-block">
          Active
            </div>
        </div>

Default Bootstrap size classes

You can use btn-lg, btn-sm and btn-xs classes for manipulating with its size.

btn-block

Also, there is a class btn-block which will extend your button to the whole block. It is very convenient in combination with Bootstrap grid.
For example, this code will show a button with the width equal to half of screen for medium and large screens; and will show a full-width button for small screens:

<div class="container">
    <div class="col-xs-12 col-xs-offset-0 col-sm-offset-3 col-sm-6">
        <button class="btn btn-group">Click me!</button>
    </div>
</div>

Check this JSFiddle out. Try to resize frame.

If it is not enough, you can easily create your custom class.