Hiking Time Calculator — Naismith's Rule
Enter your trail distance, total ascent and descent to estimate hiking time using Naismith's Rule — the standard route-planning formula used by hillwalkers and mountaineers since 1892.
Unit system
miles
ft
ft
Fitness level
3h 5m
- 1
Horizontal time
12.87 km ÷ 5 = 2.57 - 2
Ascent time
366 m ÷ 600 = 0.61 - 3
Descent correction
-0.1 = 3.08Langmuir's correction: gentle descent saves time; steep descent (> 12% grade) adds time. - 4
Fitness adjustment
3.08 × 1 = 3.08
How does this calculator work?
Naismith's Rule: Time (h) = distance_km/5 + ascent_m/600 (or miles/3.1 + feet/2000). Add Langmuir's descent correction (±10 min per 300m) and a fitness multiplier (0.8–1.5×). The result is a moving-time estimate — add 15–20% buffer for rests and navigation.
Formula
How this is calculated
Naismith's Rule, published in 1892 by Scottish mountaineer William Naismith, provides a simple planning estimate for hill-walking time: allow one hour for every 5 km (3.1 miles) of horizontal distance, plus one hour for every 600 m (2000 ft) of ascent. The two components are independent and simply added together. It has remained the standard first-approximation formula in mountain rescue and route planning for over a century.
Langmuir's modification (1984) adds a descent correction: subtract 10 minutes per 300 m of gentle descent (slopes below about 12°) to reflect that downhill walking saves time on easy ground, but add 10 minutes per 300 m of steep descent where careful footwork slows progress. This calculator applies the gentle-descent correction by default unless the average descent grade exceeds 12%.
The fitness multiplier (based on Tranter's corrections) scales the base time up or down for personal fitness. A very fit hiker might complete a route in 80% of the Naismith estimate; an unfit or heavy-pack group might need 125–150%. The formula does not account for rest stops, navigation time, difficult terrain, altitude effects, or group size — add a 10–25% buffer for real-world planning.
Frequently asked questions
For straightforward hill walking with light packs, Naismith's Rule is typically accurate to within 10–20% for an averagely fit group. It tends to underestimate on very rough or boggy terrain, on very steep descents, and for heavily loaded parties. Always add a buffer when planning in uncertain conditions.
On gentle to moderate slopes (< 12° grade) downhill walking is faster than the flat rate and Naismith's correction reduces the time. On steep, loose or rocky descents the pace actually slows below the flat rate and Langmuir's correction adds time. This calculator uses the gradient to decide which case applies.
Naismith's Rule gives moving time only. A common rule of thumb is to add 10 minutes per hour of moving time for short rests, plus extra time for meal breaks, summit photography, route-finding and any technical sections. Budget generously when day length is a constraint.
Also known as
TG we-Calculate Editorial Team. (2026). Hiking Time Calculator — Naismith's Rule [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/hiking-time-calculator
TG we-Calculate Editorial Team. "Hiking Time Calculator — Naismith's Rule." TG we-Calculate. 2026. https://we-calculate.com/calculator/hiking-time-calculator.
TG we-Calculate Editorial Team, "Hiking Time Calculator — Naismith's Rule," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/hiking-time-calculator
@misc{wecalculate_hiking_time_calculator, title = {Hiking Time Calculator — Naismith's Rule}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/hiking-time-calculator}}, year = {2026}, note = {TG we-Calculate} }
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