How long will the hike take?
Enter the distance, climb and descent of each section and see the time by Naismith, Langmuir and Tobler.
This is a planning aid, not a safety assessment. Real hiking time depends on your fitness, load, the terrain, the weather and the daylight you have. Carry navigation, water, food and warm layers, tell someone your plan, and turn around when the time or the conditions say so. How we check our calculators.
Climb and descent are the total height gained and lost in that section. Put uphill and downhill stretches in separate sections.
Three ways to estimate how long a hike takes
A map gives you distance and elevation, not time. Hikers have used simple rules to turn the first two into the third for well over a century. This calculator applies three of them to the same route so you can see how far they disagree, because they do. The figure to plan with is a range, not a single number.
The methods and their variables
Naismith's rule adds two times: distance divided by 3 mph (5 km/h), and total climb divided by 2,000 feet (600 m) per hour. It was written in 1892 by W. W. Naismith, a founder of the Scottish Mountaineering Club, and it ignores descent. Langmuir's correction, from Eric Langmuir's Mountaincraft and Leadership, keeps Naismith's base speed and changes the descent: on a gentle descent of 5° to 12°, subtract 10 minutes for every 300 m (about 1,000 ft) lost; on a descent steeper than 12°, add 10 minutes for the same height, because steep ground slows people down. The angle is worked out for each section from its descent and its distance. Langmuir also gave a version for groups, 4 km/h plus one hour per 450 m of climb, which is shown in the last row of the table.
Tobler's hiking function is a smooth curve, W = 6 × e−3.5 × |S + 0.05| km/h, where S is the slope as rise over run (a 10 percent grade is S = 0.10). Waldo Tobler published it in 1993 in a report of the National Center for Geographic Information and Analysis, fitted to the walking speeds Eduard Imhof tabulated in 1950. It peaks at 6 km/h on a gentle downhill of S = −0.05 and gives about 3.13 mph on the flat. Off a trail the commonly cited adjustment is to multiply the speed by 0.6. Here S is each section's net climb divided by its distance.
Worked example
A route has a 3-mile section that climbs 2,000 feet, then a 3-mile section that descends 2,000 feet. Naismith: 3 miles is 1 hour and 2,000 feet is 1 hour, so the climbing section takes 2 hours and the descent 1 hour: 3:00. Langmuir: the descent drops 2,000 ft (610 m) over 3 miles, an angle of about 7°, which is gentle, so 20 minutes come off: 2:40. Tobler: the climb has a grade of 12.6 percent and the descent −12.6 percent, which gives 2:33, or 4:14 off trail. In metric, 12 km with 900 m of climb is 12 ÷ 5 + 900 ÷ 600 = 3:54. The three single-walker methods are 27 minutes apart on this one ordinary route, and Langmuir's group formula, which plans for the slowest member, gives 3:46, 46 minutes more than Naismith. That is the honest size of the uncertainty before your own fitness is counted.
Speed by grade, two ways
| Grade | Tobler, mph | Naismith, mph |
|---|---|---|
| −30% | 1.55 | 3.11 |
| −20% | 2.21 | 3.11 |
| −10% | 3.13 | 3.11 |
| 0% | 3.13 | 3.11 |
| +10% | 2.21 | 1.69 |
| +20% | 1.55 | 1.17 |
| +30% | 1.1 | 0.89 |
Naismith's speed on a downhill is the flat speed, because the rule gives no credit or penalty. On these numbers Tobler's function is faster than Naismith's rule on climbs and slower on steep descents. Neither is wrong; they come from different walkers on different ground, and Naismith's rule was meant as a quick mental sum, not a fitted curve.
Limits of this method
- Map distance is not trail distance. Switchbacks, detours around obstacles and wandering add length that a map measurement misses. Measure along the trail where you can, and treat a straight-line measurement as a minimum.
- The formulas do not know you. Fitness, pack weight, snow, mud, heat, altitude and the number of people in your group are not inputs. Langmuir wrote his group formula because the slowest member sets the pace.
- Only moving time. The National Park Service advises a 10-minute break every hour on Grand Canyon hikes. Add that, plus stops, to get the time you will actually spend out.
- Sources are partly secondary. Naismith's and Langmuir's rules are quoted here as reported by other publications; Tobler's formula is as printed in secondary sources. The printed fitness tables attributed to Tranter are left out because we found no primary source for them.
Common questions
What is Naismith's rule?
It is a rule of thumb from the Scottish mountaineer William W. Naismith, published in the Scottish Mountaineering Club Journal in 1892 and usually quoted as one hour for every 3 miles (5 km) on the map plus one hour for every 2,000 feet (600 m) of climbing. The calculator uses 3 miles and 2,000 feet per hour with the US units and 5 km and 600 m per hour with the metric ones; the two versions differ by about 3.5 percent. Descent counts for nothing in the original rule.
How long does it take to hike 10 miles?
On flat ground Naismith's rule gives 3 hours 20 minutes and Tobler's function 3:12 in hours and minutes (3.13 mph). Every 1,000 feet of climbing adds half an hour under Naismith's rule. A 10-mile day with 3,000 feet of climbing is therefore about 4 hours 50 minutes of walking before any rest, and a loaded pack or rough ground makes it longer.
Which method is best?
None is proven best for every hiker. Naismith's rule is simple enough to do in your head; Tobler's function was fitted to measured walking speeds on slopes and is smooth, but it is only as good as the average grade you give it. If you hike a route often, time yourself on one section and use the method that matches your own pace, then keep using that method for new routes.
Why does the calculator want sections and not just totals?
Tobler's function needs the grade of each stretch, and Langmuir's descent correction depends on how steep the descent is. A single total for a route that goes up and then down would hide both. Enter the uphill and downhill parts as separate sections. A section that has both climb and descent is treated by Tobler's function as its net climb, so a rolling section is best split in two.
How long should I rest?
The National Park Service advises at least one 10-minute break every hour on Grand Canyon hikes to rest, eat and drink. The times above are walking time only, so a 4-hour walk with hourly breaks becomes about 4 hours 40 minutes. Add time for photos, route finding, water crossings and stops at viewpoints.
Does carrying a heavy pack change the numbers?
Yes, and none of these formulas knows about it. Naismith's rule and Tobler's function describe a walker with a light load. For a pack that weighs a fifth of your body weight or more, take your own measured pace as the base. The rucking calories calculator shows how a load raises the energy cost, and the backpack weight calculator adds up what you carry.
How do I plan around daylight?
Work backward from sunset. Take the total time from this calculator, add your rests and a margin, and compare the result with the daylight your sunrise and sunset calculator shows for the trailhead. If the numbers are close, shorten the route or start earlier; a headlamp is a backup, not a plan.
This is a planning aid, not a safety assessment, and it does not replace a map, a compass, a weather forecast or the judgment of an experienced leader.
Sources: W. W. Naismith, "Excursions: Cruach Ardran, Stobinian, and Ben More," Scottish Mountaineering Club Journal 2(3), 1892, p. 136 (not opened; wording as reported); Eric Langmuir, Mountaincraft and Leadership, 4th ed., Mountain Training England and Scotland, 2013, pp. 38–39 (not opened; as reported); Waldo Tobler, "Three Presentations on Geographical Analysis and Modeling," NCGIA Technical Report 93-1, 1993 (text read; the function itself is a figure, formula as reported); National Park Service, Grand Canyon, "Hiking Tips." Related: Rucking Calories Calculator, Backpack Weight Calculator, Trail Water Calculator, Sunrise Sunset Calculator, Pace Calculator.