An adult fox weighs, on average, five to twenty pounds— the same size range as a domestic cat. Foxes eat small, easy prey like mice, rats, voles, moles, and rabbits. A fox will never attempt to prey on another carnivore, especially one that is larger than itself. Essentially all cases of non-rabid foxes “attacking” cats, dogs, and humans have occurred when the fox was cornered and acting in fear and self-defense.
It’s a good idea to keep your pets indoors and in secure, fenced areas for their general safety, and to discourage children from ever approaching wild animals. But a wild fox in your neighborhood is not a threat, and does not need to be trapped or killed.