How many calories burned walking for an hour and a half?

It depends how fast you are walking, your body weight, your degree of fitness, what kind of ground you are walking on (soft or hard) and whether the ground is flat, or a slight incline, or a hill. Typically, people of average weight, average fitness, walking on average ground, walking at an average speed, might burn about 100 calories per mile. For the average person a slow walk might be 200 calories burned in an hour and a half, while for the average person a faster walk could burn as much as 500 calories in an hour and a half.