What is the formula to convert 14K gold to troy ounces?

Multiply the total weight of the object in grams by 0.03215. Then multiple that result by the Karat weight of the item (14 in your example), and divide that total by 24.

Example:

10 gram 14K ring x .03215 = .32 troy ounces total weight, x 14/24 = .19 troy ounces of gold