How long will your hike take? Enter your distance and elevation gain and we'll estimate your time using a modified version of Naismith's Rule, adjusted for your pace and terrain.
This tool uses a modified version of Naismith's Rule, a formula developed by Scottish mountaineer William Naismith in 1892. The base calculation is 19.3 minutes per mile, plus 30 minutes for every 1,000 feet of elevation gain.
From there, a pace multiplier adjusts for how fast you're moving: Casual adds 20% to account for frequent stops, Power subtracts 15% for strong hikers who keep moving. The terrain multiplier adds extra time for rocky or technical routes, which slow everyone down more than the distance and elevation numbers suggest.
Montana Mode (Rocky/Technical, ×1.25) is pre-selected because most trails around Bozeman and the Gallatin Range involve loose rock, boulder fields, or off-trail scrambling that makes the standard formula optimistic.
Base time = (miles × 19.3) + ((elevation ft ÷ 1,000) × 30) Final time = base × pace multiplier × terrain multiplier This calculator doesn't know your elevation profile (sustained steep grades feel different than rolling terrain), your altitude, whether the trail is snow-covered, or how much weight you're carrying. Treat the result as a starting point, not a guarantee.
Most general hiking time estimates are built around well-maintained trails in temperate climates. Montana doesn't care about that. The Gallatin Range, Crazy Mountains, and Beartooths routinely throw loose talus, creek crossings, and 10,000-foot altitude at you in the same afternoon. A "5-mile hike" in Bozeman is a different animal than a 5-mile walk in a state park.
The Rocky/Technical multiplier exists because we've watched plenty of confident hikers leave the trailhead budgeting two hours for something that took four. Elevation gain is only part of the story. Once you're picking your way across a boulder field at 9,500 feet, pace drops fast. Build in a buffer. Leave earlier than you think you need to.
These estimates use a steady pace on moderate dirt trail. Rocky terrain adds roughly 15–25 minutes per the totals below, and a casual pace adds another 20%.
| Distance | Elevation Gain | Moderate Trail | Rocky / Montana Mode |
|---|---|---|---|
| 3 miles | 500 ft | 1h 20m | 1h 31m |
| 5 miles | 1,000 ft | 2h 19m | 2h 38m |
| 8 miles | 1,500 ft | 3h 39m | 4h 9m |
| 10 miles | 2,000 ft | 4h 38m | 5h 16m |
| 12 miles | 2,500 ft | 5h 25m | 6h 9m |
| 15 miles | 3,000 ft | 6h 38m | 7h 32m |