It’s time to research how powerful an electric bicycle you might be considering buying. The wattage of an ebike is a measure of how fast it can go, but you can’t necessarily convert it to MPH. A high-performance bike might reach 200 mph, while an oceangoing cargo ship may have thousands of horsepower. In general, the higher the wattage, the faster the e-bike will go. Keep in mind, however, that an ebike riding on dirt roads will result in a significantly lower speed.