https://www.grc.com/haystack.htm

Search Space Depth (Alphabet): 26+26+10 = 62
Search Space Length (Characters): 16 characters
Exact Search Space Size (Count):
(count of all possible passwords
with this alphabet size and up
to this password's length) 48,453,916,488,
902,607,769,120,106,730
Search Space Size (as a power of 10): 4.85 x 1028
Time Required to Exhaustively Search this Password's Space:
Online Attack Scenario:
(Assuming one thousand guesses per second) 15.41 thousand trillion centuries
Offline Fast Attack Scenario:
(Assuming one hundred billion guesses per second) 1.54 hundred million centuries
Massive Cracking Array Scenario:
(Assuming one hundred trillion guesses per second) 1.54 hundred thousand centuries