Get the frame of the keyboard dynamically

Just follow this tutorial from Apple and you will get what you want. Apple Documentation. In order to determine the area covered by keyboard please refer to this tutorial.

try this:

[[NSNotificationCenter defaultCenter] addObserver:self
                                     selector:@selector(keyboardWasShown:)
                                         name:UIKeyboardDidShowNotification
                                       object:nil];

- (void)keyboardWasShown:(NSNotification *)notification
{

// Get the size of the keyboard.
CGSize keyboardSize = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

//Given size may not account for screen rotation
int height = MIN(keyboardSize.height,keyboardSize.width);
int width = MAX(keyboardSize.height,keyboardSize.width);

//your other code here..........
}

Tutorial for more information