How can I change the default width of a Twitter Bootstrap modal box?

Answer 1

Altering the class model-dialog you can achieve expected result. These small tricks work for me. Hope it will help you to solve this issue.

.modal-dialog {
    width: 70%;
}

Answer 2

you can use any prefix or postfix name for modal. but you need to make sure that's should use everywhere with same prefix/postfix name.    

body .modal-nk {
        /* new custom width */
        width: 560px;
        /* must be half of the width, minus scrollbar on the left (30px) */
        margin-left: -280px;
    }

or

body .nk-modal {
            /* new custom width */
            width: 560px;
            /* must be half of the width, minus scrollbar on the left (30px) */
            margin-left: -280px;
        }

Answer 3

In Bootstrap 3 all you need is this

<style>
    .modal .modal-dialog { width: 80%; }
</style>

Most of the above answers did not worked for me !!!

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/js/bootstrap.min.js"></script>
<link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet" />

<style>
  #myModal1 .modal-dialog {
    width: 80%;
  }
  #myModal2 .modal-dialog {
    width: 50%;
  }
</style>

<button type="button" class="btn btn-primary btn-lg" data-toggle="modal" data-target="#myModal1">
  80%
</button>

<button type="button" class="btn btn-primary btn-lg" data-toggle="modal" data-target="#myModal2">
  50%
</button>
<center>
  <!-- Modal -->
  <div class="modal fade" id="myModal1" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">
    <div class="modal-dialog" role="document">
      <div class="modal-content">
        <div class="modal-header">
          <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span>
          </button>
          <h4 class="modal-title" id="myModalLabel">Modal title</h4>
        </div>
        <div class="modal-body">
          custom width : 80%
        </div>
        <div class="modal-footer">
          <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
          <button type="button" class="btn btn-primary">Save changes</button>
        </div>
      </div>
    </div>
  </div>


  <!-- Modal -->
  <div class="modal fade" id="myModal2" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">
    <div class="modal-dialog" role="document">
      <div class="modal-content">
        <div class="modal-header">
          <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span>
          </button>
          <h4 class="modal-title" id="myModalLabel">Modal title</h4>
        </div>
        <div class="modal-body">
          custom width : 50%
        </div>
        <div class="modal-footer">
          <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
          <button type="button" class="btn btn-primary">Save changes</button>
        </div>
      </div>
    </div>
  </div>

</center>

Answer 4

In Bootstrap 3 with CSS you can simply use:

body .modal-dialog {
    /* percentage of page width */
    width: 40%;
}

This ensures you don't break the design of the page, because we're using .modal-dialog instead of .modal which will be applied even to the shading.

Answer 5

Solution was taken from this page

$('#feedback-modal').modal({
    backdrop: true,
    keyboard: true
}).css({
    width: 'auto',
    'margin-left': function () {
        return -($(this).width() / 2);
    }
});

Answer 6

UPDATE:

In bootstrap 3 you need to change the modal-dialog. So in this case you can add the class modal-admin in the place where modal-dialog stands.

Original Answer (Bootstrap < 3)

Is there a certain reason you're trying to change it with JS/jQuery?

You can easily do it with just CSS, which means you don't have to do your styling in the document. In your own custom CSS file, you add:

body .modal {
    /* new custom width */
    width: 560px;
    /* must be half of the width, minus scrollbar on the left (30px) */
    margin-left: -280px;
}

In your case:

body .modal-admin {
    /* new custom width */
    width: 750px;
    /* must be half of the width, minus scrollbar on the left (30px) */
    margin-left: -375px;
}

The reason I put body before the selector is so that it takes a higher priority than the default. This way you can add it to an custom CSS file, and without worries update Bootstrap.