Swift

You can get the keyboard height by subscribing to the UIKeyboardWillShowNotification notification. (Assuming you want to know what the height will be before it's shown).

Swift 4

NotificationCenter.default.addObserver(    self,    selector: #selector(keyboardWillShow),    name: UIResponder.keyboardWillShowNotification,    object: nil)

@objc func keyboardWillShow(_ notification: Notification) {    if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {        let keyboardRectangle = keyboardFrame.cgRectValue        let keyboardHeight = keyboardRectangle.height    }}

Swift 3

NotificationCenter.default.addObserver(    self,    selector: #selector(keyboardWillShow),    name: NSNotification.Name.UIKeyboardWillShow,    object: nil)

@objc func keyboardWillShow(_ notification: Notification) {    if let keyboardFrame: NSValue = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue {        let keyboardRectangle = keyboardFrame.cgRectValue        let keyboardHeight = keyboardRectangle.height    }}

Swift 2

NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)

func keyboardWillShow(notification: NSNotification) {        let userInfo: NSDictionary = notification.userInfo!        let keyboardFrame: NSValue = userInfo.valueForKey(UIKeyboardFrameEndUserInfoKey) as! NSValue        let keyboardRectangle = keyboardFrame.CGRectValue()        let keyboardHeight = keyboardRectangle.height    }

Swift 3.0 and Swift 4.1

1- Register the notification in the viewWillAppear method:

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)

2- Method to be called:

@objc func keyboardWillShow(notification: NSNotification) {    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {        let keyboardHeight = keyboardSize.height        print(keyboardHeight)    }}

Swift 4 and Constraints

To your tableview add a bottom constraint relative to the bottom safe area. In my case the constraint is called tableViewBottomLayoutConstraint.

@IBOutlet weak var tableViewBottomLayoutConstraint: NSLayoutConstraint!override func viewWillAppear(_ animated: Bool) {    super.viewWillAppear(animated)    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillAppear(notification:)), name: .UIKeyboardWillShow, object: nil)    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillDisappear(notification:)), name: .UIKeyboardWillHide, object: nil)}override func viewWillDisappear(_ animated: Bool) {    super.viewWillDisappear(animated)    NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow , object: nil)    NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide , object: nil)}@objc func keyboardWillAppear(notification: NSNotification?) {    guard let keyboardFrame = notification?.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue else {        return    }    let keyboardHeight: CGFloat    if #available(iOS 11.0, *) {        keyboardHeight = keyboardFrame.cgRectValue.height - self.view.safeAreaInsets.bottom    } else {        keyboardHeight = keyboardFrame.cgRectValue.height    }    tableViewBottomLayoutConstraint.constant = keyboardHeight}@objc func keyboardWillDisappear(notification: NSNotification?) {    tableViewBottomLayoutConstraint.constant = 0.0}