Calculate a hike’s difficulty rating from distance and elevation gain using Shenandoah National Park’s formula, or find the distance or gain for a rating.
Shenandoah Rating Formula
Shenandoah National Park publishes a named numerical method for comparing hikes from two route facts: distance in miles and total elevation gain in feet. The equation is rating = square root of (2 x elevation gain x distance). This calculator applies that formula directly and can also rearrange it to solve for distance or elevation gain at a selected numerical rating.
For distance mode, square the target rating and divide by twice the elevation gain. For elevation-gain mode, square the target rating and divide by twice the distance. The calculator converts kilometers to miles and meters to feet before using the formula, then reports the route facts in both unit systems.
| Numerical result | Descriptor used here | Boundary handling |
|---|---|---|
| Below 50 | Easiest | Any result below 50 |
| 50 to below 100 | Moderate | 50 included |
| 100 to below 150 | Moderately Strenuous | 100 included |
| 150 through 200 | Strenuous | 150 and 200 included |
| Above 200 | Very Strenuous | Any result above 200 |
At shared endpoints in the NPS wording, this calculator assigns 100 to Moderately Strenuous and 150 to Strenuous; 200 remains Strenuous. Classification uses the unrounded numerical score. A zero-gain route receives zero regardless of its positive distance, a limitation for long flat hikes. Distance cannot be uniquely recovered from zero gain and zero rating.
Worked Example
For a 10-mile hike with 2,200 feet of total elevation gain, multiply 2 by 2,200 by 10. The product is 44,000. Its square root is approximately 209.76, which falls above 200 and receives the Very Strenuous descriptor under this named method. In reverse, a target rating of 150 with 2,000 feet of gain yields 150 squared divided by 4,000, or 5.625 miles.
What the Number Does and Does Not Measure
The rating is a compact distance-and-elevation comparison. Two hikes with the same score can still feel different because one may be steep and short while another is long and gradual. The formula does not measure scrambling, stream crossings, trail condition, heat, cold, exposure, route finding, current closures, or an individual’s experience. Use the displayed route facts alongside current park information rather than treating the descriptor as a complete safety judgment.
Entering Route Data Consistently
Use total route distance for the exact itinerary being compared and cumulative elevation gain rather than the difference between the trailhead and highest point. An out-and-back route needs the full traveled distance. If a mapping source reports metric measurements, select kilometers and meters beside the inputs; conversion occurs before the equation is evaluated.
Sources
National Park Service: How to Determine Hiking Difficulty, Shenandoah National Park
National Institute of Standards and Technology: Handbook 44, Appendix C, General Tables of Units of Measurement, 2026.
