I used the following calculator to estimate mine at 52.5.
From the same website:
MAX VO2 functionally represents the maximum amount of oxygen that can be removed from circulating blood and used by the working tissues during a specified period. World class endurance athletes generally have high readings. Maximum Oxygen Update (Max VO2) values for selected groups and individuals are as follows:
Although precise measurements are done on a treadmill with equipment measuring oxygen uptake, you can estimate yours from a recent running race. The race distance should be between about one mile and a marathon (or about 1500 meters to 50 km). Distances outside this range will not give meaningful results, since performance is limited by factors other than VO2 MAX.