To calculate the maximum attempts it would take to crack a password.  You need to take the number of allowable character values and raise that value by the number of populated positions in the password.  This calculation only works if each position in the password allows the same number of character values.  Ahh its to early for this math.

Examples:

4-character password with 17 allowable character values

17*17*17*17 = 83,521 attempts

17⁴ = 83,8521 attempts

 

63⁴ = 15,752,961 attempts

 

17⁷² = 3.911310908 +88

For an online calculator go to http://www.motionnet.com/calculator/

Now if you are wondering how long it will take to crawk a password, I will need to refer you to a site that tries to estimate it

http://www.lockdown.co.uk/?pg=combi&s=articles