# John the Ripper - Calculating brute force time to crack password

I'm using incremental mode (brute force) mode in John the Ripper to crack Linux MD5 passwords. I'm trying to calculate the time it will take to run through all combinations of 12 passwords (with 12 different salts for each password).

Using a 95 character count and a max length of 6 characters, there are 735,091,890,625 combinations (95^6).

Since each password is salted that puts us at (735,091,890,625 x 12) 8,821,102,687,500 hashing calculations.

When I run John the Ripper it's usually running at 1133p/s 14273c/s 14273C/s.

So...8,821,102,687,500 / 14273 = 618,027,232.36 seconds

51,502,269.36 / 60 = 10,300,453.87 minutes

858,371.16 / 60 = 171,674.23 hours

14,306.19 / 24 = 7,153.09 days

I realize there's always the possibility that a password will be cracked early. However, have I calculated that correctly? It will take 7,153.09 days (at the very maximum) to run through all combinations?

• Your calculation is not correct. Check this `8,821,102,687,500 / 14273` again. Oct 4 '14 at 2:45
• Good catch. Edited with fixes. Oct 4 '14 at 6:18
• Radeon 9790 82.G c/s --> your case: 107 seconds, oclHashCat-lite. Feb 11 '20 at 11:44