This table shows the chance for a list of hash rates, to find a block in one day
at the current network Difficulty: Nd = 50,646,206,431,058.1 = 50.6T

Hash Rate   Chance in a day
1GH/s   1 in 2517636577
5GH/s   1 in 503527315
100GH/s   1 in 25176366
300GH/s   1 in 8392122
600GH/s   1 in 4196061
1TH/s   1 in 2517637
10TH/s   1 in 251764
50TH/s   1 in 50353
100TH/s   1 in 25176
1PH/s   1 in 2517.6
5PH/s   1 in 503.53
10PH/s   1 in 251.76
100PH/s   1 in 25.176
200PH/s   1 in 12.588

You can see that as the hash rate goes up 10x the chance gets 10x better.