A variety of factors affect how many calories you burn walking six miles, including weight, gender, age, metabolism, body composition and how fast you walk.
If you weigh 150 pounds and walk at the rate of 3 mph, it will take two hours to walk six miles and you will burn 450 calories, according to A Calorie Calculator. If you weigh 200 pounds and walk at 3 mph, you will burn 598 calories. At 250 pounds, you burn 748 calories.
If you walk at 4 mph, it will take you 90 minutes to cover six miles. You burn 510 calories if you weigh 150 pounds, 680 calories at 200 pounds and 850 calories at 250 pounds, according to A Calorie Calculator.
Cover those six miles at a more brisk pace of 5 mph and it will take you 72 minutes. At 150 pounds, you burn 653 calories. You burn 871 calories if you weigh 200 pounds and 1,089 calories if you weigh 250.