The amount of time it takes to bake a cake in a convection oven will vary depending on the size and shape of the cake, the recipe you are using, and the power of your oven. However, as a general rule of thumb, you can expect to bake a cake in a convection oven for about 25-30% less time than you would in a conventional oven. For example, if a recipe calls for baking a cake at 350 degrees Fahrenheit for 30 minutes in a conventional oven, you would bake it at 325 degrees Fahrenheit for 22-25 minutes in a convection oven.