How long would it take to crack my password

http://www.itworld.com/security/280486/how-long-would-it-take-crack-my-password?page=0,1

How long would it take to crack my password: (Includes letters and numbers, no upper- or lower-case and no symbols)

6 characters: 2.25 billion possible combinations

• Cracking online using web app hitting a target site with one thousand guesses per second: 3.7 weeks.
• Cracking offline using high-powered servers or desktops (one hundred billion guesses/second): 0.0224 seconds
• Cracking offline, using massively parallel multiprocessing clusters or grid (one hundred trillion guesses per second: 0.0000224 seconds

10 characters: 3.76 quadrillion possible combinations

• Cracking online using web app hitting a target site with one thousand guesses per second: 3.7 weeks.
• Cracking offline using high-powered servers or desktops (one hundred billion guesses/second): 10.45 hours
• Cracking offline, using massively parallel multiprocessing clusters or grid (one hundred trillion guesses per second: 37.61 seconds.

Add a symbol, make the crack several orders of magnitude more difficult:

6 characters: 7.6 trillion possible combinations

• Cracking online using web app hitting a target site with one thousand guesses per second: 2.4 centuries.
• Cracking offline using high-powered servers or desktops (one hundred billion guesses/second): 1.26 minutes
• Cracking offline, using massively parallel multiprocessing clusters or grid (one hundred trillion guesses per second: 0.0756 seconds

10 characters: Possible combinations: 171.3 sextillion (171,269,557,687,901,638,419; 1.71 x 1020)

• Cracking online using web app hitting a target site with one thousand guesses per second: 54.46 million centuries.
• Cracking offline using high-powered servers or desktops (one hundred billion guesses/second) 54.46 years
• Cracking offline, using massively parallel multiprocessing clusters or grid (one hundred trillion guesses per second: 2.83 weeks.