Trail Difficulty Rating Calculator
Turn a trail’s distance and elevation gain into a single difficulty number with the Shenandoah rating, plus Petzoldt energy miles as a second read on the effort.
Compare trails on one honest scale
Guidebook labels like “moderate” mean different things to different authors. A numerical rating built from distance and climb gives you a consistent way to line up two trails and know which will actually work you harder — and whether a route is within your group’s reach today.
Turn the effort into a time with the Hiking Time Calculator, and make sure the day fits the daylight with the Daylight Turnaround Calculator.
Frequently Asked Questions
How is the difficulty rating calculated?
It uses the numerical rating popularised by Shenandoah National Park: the square root of twice the elevation gain in feet times the distance in miles. A 10-mile hike with 3,000 feet of climb scores about 245. The bands run from 'easiest' under 50 to 'very strenuous' over 200. Folding distance and climb into one number lets you compare very different trails on a single scale.
What are Petzoldt energy miles?
Paul Petzoldt, a founder of American wilderness education, taught hikers to add one 'energy mile' for every 1,000 feet of elevation gain on top of the actual distance. A 10-mile hike with 3,000 feet of climb therefore feels like about 13 energy miles of effort. It is a quick mental model for why a short, steep trail can be harder than a longer, flatter one, and we report it alongside the Shenandoah rating.
Does the rating account for terrain and conditions?
No — it measures only distance and elevation gain. A rocky, exposed, or poorly maintained trail can feel far harder than its number suggests, and mud, snow, heat, or altitude all add difficulty the formula cannot see. Use the rating to compare routes and gauge effort, then read a recent trail description and the forecast before you commit.
How do I turn a rating into a time?
The rating tells you how hard, not how long. For a time estimate, put the same distance and gain into the hiking time calculator, which applies Naismith's rule, then set a safe turnaround with the daylight calculator. Together they turn 'this looks tough' into a concrete start time and turnaround.
The rating measures distance and climb only — it cannot see rough footing, exposure, weather, or altitude. Read a recent trail description and the forecast before you commit. Planning aid, not a safety guarantee.