I know that there is a window where time machine can display its current progress, along with an estimate about how long it will likely take till the current backup is complete. This window did somehow appear during my initial backup. However, I currently can't find a way to manually open that window for a subsequent backup. Yes there is the Time Machine tab in the Control Panel, but that will not provide an estimation of remanining time. Neither does the context menu of the menu bar icon. So how can I get that window?
I am 100% sure there is no way to see how long the the backup takes just the size of the backup and how much portion of the size it has already backed up like shown below.
The only time duration that Time Machine shows is when you are restoring from a backup and during the first time you set up Time Machine using a empty hard disk.
I just noticed that "Open Time Machine Preferences" shows a progress bar for the current backup operation. I just upgraded to Maverick recently so this may be a new feature.