The Crude Fatality Rate (CFO) = number of deaths/number of cases​

The Case Fatality Rate (CFO) = number of deaths/(number of deaths + number of recoveries)​

We will hear many numbers on fatality rate. Nobody will know until it's over. For instance, with SARs, there were about 800 deaths and 8,000 cases. The fatality rate was 10%. Of course, that's open to interpretation.The following info comes from here Each ratio has its own use in an environment where the real numbers can't be known until it's over. Even then, there will be differences in measurement techniques.I added the highlighted columns to the table on this website.I'm 66 and reserve the right to be wrong or to change my interpretation at any time. This is not a substitute for recommendations from reliable sources.