Hiking Time Calculator (Naismith's Rule)

Naismith's rule and its corrections

William Naismith, a Scottish mountaineer, wrote the rule in 1892: allow one hour per three miles on the map, plus one extra hour per 2,000 feet of ascent. It is still the base formula for trail planning. The calculator divides distance by three, adds climb divided by 2,000, and gives a moving time before stops. It is simple, which is why it lasted.

Two later corrections help. Tranter adjusted the rule for fitness and fatigue, since a beginner takes longer than a mountaineer. Wikipedia describes his method as using a table keyed to how fast you climb 1,000 feet. This tool uses simpler multipliers from 0.85 to 1.5 as a stand-in, not Tranter's table. Langmuir added descent: subtract 10 minutes per 300 meters (about 984 feet) on gentle slopes of 5 to 12 degrees, and add 10 minutes on steeper ones.

Here is the default example. An 8-mile hike with 2,500 feet of climb gives 2.67 hours for distance plus 1.25 hours for climb, so 3.9 hours. With the typical factor and a 30-minute break, the total is about 4.4 hours. Switch the descent to gentle and you save about 25 minutes. Switch to steep and you add about 25 minutes. Choose the descent terrain that matches the route.

Use the result as a planning baseline, not a promise. Groups move at the speed of the slowest hiker. Carrying more weight slows you, so check your load with the pack weight calculator and plan drinks with the hiking water calculator. For calories burned on the trail, see AthleteCalcs, our sister site for fitness and nutrition math. Always leave extra time before dark. Write down a turnaround time before you start, and stick to it even if you feel strong, because the return trip on tired legs is usually slower than the way out.

Where these numbers come from

The formulas and default values in this calculator are based on:

• Wikipedia, Naismith's rule (en.wikipedia.org/wiki/Naismith%27s_rule), for the 1892 rule, Tranter's fitness corrections and Langmuir's 1984 descent corrections. Note: fitness multipliers are simplified stand-ins for Tranter's table

This is a planning estimate, not medical, legal or immigration advice. Fees, allowances, limits and entry rules change, so confirm the figures with your airline, cruise line, customs agency or the official government source before you book or travel, and follow their rules if they differ from this page.