Naismith’s Rule is a rule of thumb that helps in the planning of a walking or hiking expedition by calculating how long it will take to walk the route, including ascents. The rule was devised by William W. Naismith, a Scottish mountaineer, in 1892. The basic rule is as follows:
Light easy going – 5 km per hour.
Easy going – 3 km per hour.
Heavy going – 1½ km per hour.
Thick bush, heavy going – ½ km per hour.
Climbing 500m add 1 hour.
Descending 1000m add 1 hour.
For every hour after 5 hours add 1 hour (for fatigue).
(1/3 reduction for fit experienced walkers).
For more information please visit the Wikipedia here.
This is a really handy piece of info if you are planning a hike in Cubs or Scouts.