This is a two part question: How can you position the modal vertically in the center when you don't know the exact height of the modal? Is it possible to have the modal centered and have overflow:auto in the modal-body, but only if the modal exceeds the screen height? I have tried using this: .modal-dialog { height: 80% !important; padding-top:10%; } .modal-content { height: 100% !important; overf