An average person can walk one mile on a flat, well-groomed surface in 17 to 20 minutes. A fit person walking briskly can walk a mile in 13 minutes. An estimated average walking speed for calculating how long a hike or walk will take is around 3 miles per hour.
Over rough terrain, the average walking speed can drop to 2.5 miles per hour. Climbing and descending hills can significantly slow down a walker. For example, walking 10 miles over flat terrain is estimated to take the average person 4 hours. However, walking the same distance up and down a 1640-foot-high hill increases the estimated walking time to 5 hours and 10 minutes.