Hiking Trail Difficulty

Defining the difficulty of a hike is mostly an objective process, but there are a few tested formulas that deduce a numerical value to represent trail difficulty. Below are two of the most common formulas, both of which are used on our site.

Note: Because many trails in the Great Smoky Mountains can be turned into loop hikes, our trail pages only use these formulas to calculate the one way distance based on elevation gain and mileage. Our calculations do not assume round trip distance.

The above list of hiking trails in the Smokies is incomplete and constantly being updated. If you have information or photos you would like to contribute, please contact caroline@pigeonforge.com.

Paul Petzoldt's "Energy Mile"

Paul Petzoldt, the founder of the National Outdoor Leadership School (NOLS), developed the "Energy Mile" formula for calculating the difficulty level of hike in 1976. He defined one energy mile as the energy required to walk one mile on flat ground. Petzoldt recommended adding two energy miles for each 1000 feet of elevation gained. Factors such as hiker weight and backpack weight create some variance in the difficulty, but Petzoldt's energy mile theory is widely considered one of the most accurate formulas for calculating trail difficulty.

Paul Petzoldt’s “Energy Mile” Formula: distance in miles plus elevation gain divided by 500

< 5 = Easy

5 - 10 = Moderate

> 10 = Strenuous

Source: The Validity of Petzoldt's Energy Mile Theory

Shenandoah Hiking Difficulty

Another commonly used trail difficulty scale is one developed by Shenandoah National Park in Virginia. The Shenandoah scale offers a wider range of possibilities in defining the difficulty of a hike.

Shenandoah National Park scale: square root of double the elevation gain multiplied by the distance in miles
  • < 50 = Easiest (suitable for anyone who enjoys walking)
  • 50 - 100 = Moderate (suitable for novice hikers)
  • 100 - 150 = Moderately Strenuous (challenging for an unconditioned person)
  • 150 - 200 = Strenuous (challenging for most hikers)
  • > 200 = Very Strenuous (only for well conditioned and prepared hikers)

Source: How to Determine Hiking Difficulty - Shenandoah National Park (U.S. National Park Service)

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