If you want your coffee to give you a big kick-start, you might grab a light roast, having heard that it has the most caffeine. The good news: light roasts are delicious and worth drinking regardless of caffeine content. The bad news: you’re the victim of one of the most pernicious myths in coffee. All other factors being equal, dark and light roasts tend to have about the same amount of caffeine.

The myth that light roast coffee has more caffeine than dark roasts is based on the assumption that as beans are roasted, they lose caffeine. However, caffeine is a very stable compound, and beans would need to be roasted for a long time at a very high temperature—longer and higher than roasters typically use—to lose much caffeine content. Beans simply do not lose much caffeine between the phases that define a light and a dark roast. Moreover, dark roasted beans are more porous than light roasted beans, so more soluble material is extracted into brew water, meaning dark roasts release slightly more caffeine during brewing than light roasts. Light roast beans are also denser than dark roast beans, so if you measure your ground coffee by mass, you’re likely to use fewer beans per cup of coffee with a light roast than a dark roast. Fewer beans means less available caffeine to end up in your brewed cup of coffee.

Beyond all that, there are many other factors that influence how much caffeine a cup of coffee has, such as your brew method, brew duration, coffee varietal, grind size, water temperature, and more. Given how many variables influence the final caffeine level in your cup, the best guidance might be: choose your coffee based on what you enjoy.