Ceiling fans use less than 100 watts on average when turned on at high speed. The actual number of watts used differs among ceiling fans depending on the size and number of blades, the brand and the type of motor.
To give some examples, one particular Westinghouse ceiling fan with 24-inch blades utilizes 31 watts. A ceiling fan with 52-inch blades of the same brand utilizes more energy at 58 watts. A fan of the Hunter brand with the same size blades, however, utilizes 87 watts. To find out the exact wattage of a unit, check the product label or manual.