What is the top bar height of iPhone X?

You can programmatically obtain the navigation bar's height by using safeAreaInsets on the view in the contained view controller:

let navBarHeight = view.safeAreaInsets.top

This will account for whether it's a large title navigation bar or not, and whether or not there's a search bar attached to it.

See the safeAreaInsets documentation for more information.

You can use the navigation bar's .frame property to figure out the overall height of the top bar area:

Swift 5.0:

let xBarHeight = (self.navigationController?.navigationBar.frame.size.height ?? 0.0) + (self.navigationController?.navigationBar.frame.origin.y ?? 0.0)

ObjC:

CGRect navbarFrame = self.navigationController.navigationBar.frame;
float topWidth  = navbarFrame.size.width;
float topHeight = navbarFrame.size.height + navbarFrame.origin.y;

I suppose this is a bit of a cheat, but adding the navbar's height with its y origin seems to give the correct total height regardless of device.

Nav bar is 44pt as usual (when no large titles) and the status bar has increased from 20pt to 44pt. Here's what you can type in the debugger to verify it:

The display on iPhone X, however, is 145pt taller than a 4.7" display, resulting in roughly 20% additional vertical space for content.

for more information you get HIG for iphone X from apple documents and detail description in here1 and here2

status bar height

previously 20pt, now 44pt

Because of the sensors on top of the display, the new status bar is split in 2 parts. If your UI is doing something special with that space (previously 20pt high, now 44pt), because it will be taller on the iPhone X. Make sure that it can be dynamically changed in height. A great thing is that the height won’t be changed if a user makes a phone call or is using a navigation app, which was previously the case on other iPhones.

portrait

Navigation bar height as normal 88 and large title time 140

• Standard title - 44pt (88pt with Status Bar)
• Large title - 140pt
• bottom bar - 34pt

Landscape

• Standard title - 32pt
• bottom bar - 21pt