select multiple songs from within a large playlist, and instantly get an update at top/bottom of how long the selected songs will last and how many you have selected

Be able to select multiple songs from within a large playlist, and instantly get an update at top/bottom of how long the selected songs will last and how many you have selected. The reason for this I have created a very large playlist of songs.. I want to be able to select a group of songs for when I throw parties etc... but need to know that the amount of songs I have selected will last long enough. I have noticed that a total of the playlist is now seen at the top.. but can it do it in real time as you multiple select songs?