The Scoville heat scale ranks cayenne pepper an eight, which indicates 50,000 to 100,000 Scoville heat units. Other peppers with this rating include Santaka, super chile, pequin and Jaloro.
Wilbur Scoville developed the Scoville heat scale in 1912. The scale assigns a heat level to peppers based on their capsaicin content. The scale starts at zero, which indicates that some peppers have a negligible amount of heat, including sweet bell peppers, banana peppers and pimentos. The scale goes up to 10, which indicates the hottest peppers with 350,000 to 2,100,000 Scoville heat units. Some peppers rated 10 on the scale include chocolate habanero, Jamaican hot, Trinidad scorpion and ghost peppers.