Hiking Time Calculator: Naismith's Rule

Hiking time calculator (Naismith's rule)

Short answer

Naismith's rule allows one hour for every 3 miles (about 5 km) on the map plus one hour for every 2,000 ft (610 m) of climbing. A 12 km hike with 800 m of ascent comes to about 3 h 48 min of moving time, before breaks. Tobler's hiking function puts the fastest walking at about 6 km/h on a gentle 5% downhill.

Last reviewed 28 October 20262 published sourcesNot medical advice

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Tobler's walking speed on a trail by slope
Slope	km/h	mph
20% downhill	3.6	2.2
10% downhill	5.0	3.1
5% downhill	6.0	3.7
Flat	5.0	3.1
5% uphill	4.2	2.6
10% uphill	3.6	2.2
20% uphill	2.5	1.6
30% uphill	1.8	1.1

Slope

km/h

mph

20% downhill

3.6

2.2

10% downhill

5.0

3.1

5% downhill

6.0

3.7

Flat

5.0

3.1

5% uphill

4.2

2.6

10% uphill

3.6

2.2

20% uphill

2.5

1.6

30% uphill

1.8

1.1

How the estimate works

Naismith's 1892 rule is "an hour for every three miles on the map, with an additional hour for every 2000 feet of ascent"; the metric equivalents are 4828 m and 610 m (Irmischer & Clarke, 2018). The calculator uses the rule's own miles and feet and converts your units.

The rule implies that 1 m of climbing costs as much time as 7.92 m on the flat. An analysis of race records found male runners and walkers trade climb for distance at about 1:8 and female ones at about 1:10 (Scarf, 2007). The calculator shows your route's flat-ground equivalent on that 1:7.92 basis.

Tobler's hiking function, speed = 1.67 × e^(−3.5 × |slope + 0.05|) metres per second, gives the speeds in the table; off trail, it is often multiplied by 0.6 (Irmischer & Clarke, 2018).

Planning a run instead of a walk? Use the pace calculator. For the energy a hike uses, see the calories burned calculator.

Common questions

What is Naismith's rule?

In 1892, Naismith suggested allowing an hour for every three miles on the map, with an additional hour for every 2,000 feet of ascent. In metric that is about 4.8 km an hour plus an hour per 610 m of climbing.

Is Naismith's rule accurate?

It is a starting point for a fit walker on a path, with no stops. It treats 1 m of climbing as worth 7.92 m of flat walking; an analysis of race records suggested about 1:8 for male and 1:10 for female runners and walkers. Add time for breaks, rough ground, a heavy pack, a group or bad weather.

What is Tobler's hiking function?

Tobler's formula gives walking speed from slope: speed = 6 × e^(−3.5 × |slope + 0.05|) km/h on a trail. It is fastest, about 6 km/h, on a 5% downhill and slows on steeper climbs and descents.

Sources

Figures on this page were checked against these publications on 28 October 2026.

Irmischer IJ, Clarke KC. Measuring and modeling the speed of human navigation. Cartography and Geographic Information Science. 2018;45(2):177–186. doi.org/10.1080/15230406.2017.1292150

Scarf P. Route choice in mountain navigation, Naismith's rule, and the equivalence of distance and climb. Journal of Sports Sciences. 2007;25(6):719–726. doi.org/10.1080/02640410600874906

Hiking time calculator (Naismith's rule)