How Naismith's rule works
Naismith's rule is a simple formula hikers have used since 1892 to estimate walking time: allow one hour for every 5 km (3 miles) of horizontal distance, plus one extra hour for every 600 m (2,000 ft) of ascent. This calculator adds those two components together, then lets you adjust for your own pace and add rest stops.
The result is a rough planning estimate, not a guarantee. Terrain, weather, trail conditions, pack weight and fitness all change real hiking time, often by 20-50% in either direction.
Time = (distance ÷ 5 km) hours + (ascent ÷ 600 m) hours, then multiplied by your pace setting and added to rest time
This is a 19th-century rule of thumb, not a safety guarantee. Always add extra time for weather, fatigue and the unexpected, and tell someone your planned route and return time before you go.
How long will my hike take
Naismith's rule estimates hiking time as one hour per 5 km of distance plus one hour per 600 m of ascent. An 8 km walk with 600 m of climbing takes about 2 h 36 m at the standard pace, before adding rest stops.
Steps
- Enter the horizontal distance of your route in kilometers (or switch to miles).
- Enter the total elevation gain — the sum of all uphill climbing, not just net altitude change.
- Choose a pace setting if you want to nudge the estimate faster or slower than the standard Naismith pace.
- Enter any planned rest time in minutes; it is added on top of the moving-time estimate.
- Read the total estimated time, and the breakdown of how it was calculated.
Formula
time = (distance ÷ 5 km) hours + (ascent ÷ 600 m) hours, × pace multiplier, + rest time
- distance ÷ 5 km = hours for the flat/horizontal component
- ascent ÷ 600 m = extra hours for the climbing component
- pace multiplier: your own adjustment, not part of the original 1892 formula
- rest time: added after the pace adjustment, not multiplied by it
Example estimates (Naismith base time, before pace adjustment)
| Hike | Distance | Ascent | Rest | Estimated time |
|---|
| Easy valley walk | 5 km | 200 m | 0 min | 1 h 20 m |
| Half-day hill walk | 8 km | 600 m | 15 min | 2 h 51 m |
| Full-day mountain hike | 15 km | 1,000 m | 30 min | 5 h 10 m |
| Multi-summit ridge traverse | 20 km | 1,500 m | 45 min | 7 h 15 m |
| Short steep climb | 4 km | 800 m | 10 min | 2 h 18 m |
Frequently asked questions
What is Naismith's rule?
It's a formula proposed by Scottish mountaineer William W. Naismith in 1892: one hour for every 5 km walked, plus one hour for every 600 m climbed. It's still the standard starting point for estimating hiking time in mountaineering.
How accurate is it?
It was designed as a baseline for a fit hiker moving continuously, so most people take longer. Mountaineering literature commonly notes it underestimates time for tired, heavily loaded or less experienced hikers, sometimes by 25% or more, which is why this calculator lets you apply a slower pace multiplier.
Does it account for downhill sections?
No — the classic rule only adds time for ascent, not descent. A later adjustment called the Langmuir correction subtracts a little time for gentle descents and adds time for steep ones, but this calculator does not apply it; treat downhill time as included in the flat-distance component.
What is the pace multiplier based on?
It is not an official correction — Naismith's rule itself has no built-in fitness adjustment. The slower/faster options here are a convenience for you to nudge the base estimate; a formal fitness correction (Tranter's correction) exists in mountaineering literature but requires a separate fitness test this calculator does not perform.
Should I add extra time beyond this estimate?
Yes. Treat the result as a minimum moving-time estimate and add a safety margin for weather, navigation, group size and daylight — mountain safety guides consistently recommend planning conservatively rather than to the exact estimated time.
Naismith's rule ignores terrain difficulty, trail surface, weather, pack weight, group size and daylight hours, and the classic formula does not subtract any time for descent. It was devised in 1892 for a fit hiker moving at a steady pace, so it tends to underestimate the time needed by less experienced or heavily loaded hikers. Use this only as a starting point for planning, not as a safety guarantee.
Sources: Naismith's rule — Wikipedia, W. W. Naismith, Scottish Mountaineering Club Journal (1892), Tranter's correction; Langmuir's descent correction (mountaineering literature)