1 kH/s is 1,000 hashes per second (sometimes mistakenly written KH/s). 1 MH/s is 1,000,000 hashes per second. 1 GH/s is 1,000,000,000 hashes per second. 1 TH/s is 1,000,000,000,000 hashes per second. 1 PH/s is 1,000,000,000,000,000 hashes per second.