You can listen to the resize event in componentDidMount() and then update the dimensions (width and height). You should remove the listener in componentWillUnmount() method.
resize
componentDidMount()
width
height
componentWillUnmount()
class WindowDimensions extends React.Component { constructor(props){ super(props); this.updateDimensions = this.updateDimensions.bind(this); } componentWillMount() { this.updateDimensions() } componentDidMount() { window.addEventListener('resize', this.updateDimensions) } componentWillUnmount() { window.removeEventListener('resize', this.updateDimensions) } updateDimensions() { this.setState({width: window.innerWidth, height: window.innerHeight}) } render() { return <span>{this.state.width} x {this.state.height}</span> } }