Burn 3,500 calories and you're there. So if you weigh 150 pounds and walk at a 4 mph pace for an hour a day, a pound could be gone in just over 10 days -- without dieting! Check out how much you're burning every hour you walk: Weight: 120 lb. Pace / Calories burned/hour. 24-minute mile (2.5 mph) / 163. 20-minute mile (3 mph) / 180. 17-minute mile (3.5 mph) / 207. 15-minute mile (4 mph) / 272. Weight: 150 lb.