There is not a lot of data on the success rate of leopards hunting because they are secretive, solitary and often nocturnal to avoid humans. I am referring to the leopards of Africa. They are sometimes called ‘common leopards’.
Estimates indicate that the leopard is not highly successful in hunting. T.N. Bailey in The African Leopard (1993) states that leopards were successful in 2 out of 13 hunting attempts (15% success rate). During the daytime it is worse at 0%. B.C.R. Bertram in Leopard ecology as studied by radio tracking (1982) stated that in the Serengeti 3 out of 64 daytime hunts observed and recorded were successful (5%). He stated that he believed that the success rate was higher at night.
G.B. Schaller in The Serengeti lion (1972) stated that he observed 9 daytime hunts out of which 1 was successful (11%). P.E. Sander and P.J. Haden in The ecology of asociality in Namibian leopards (1997) said that leopards in northeastern Namibia had a success rate of 38.1% in averaging 1 kill every 2.7 hunts.
Lastly, J. du P Bothma and E.A.N. Riche in Aspects of the ecology and behaviour of the leopard Panthera pardus in the Kalahari Desert (1984) wrote that male leopards had a kill rate of 12% (6 kills out of 74 attacks). They state that the female leopard-with-cubs kill rate was better at 23% (7 out of 25 cases). Most of the hunts involved medium sized prey while small prey items were seldom chased.
I suppose you could average these success rates and if you did the figure would be 15%.
SOME MORE ON THE LEOPARD: