Day

May 9, 2019

9
May
2019
3

Why we’re adjusting Naismith’s Rule

Guest blog by OS product manager Tim Newman.

If you’ve spent any time hillwalking or learning basic navigation skills, then chances are you’ve heard of Naismith and his eponymous rule for estimating walking times. It enables you, armed only with a paper map and a piece of string, to predict your route time or assess whether you’re quicker heading straight over a hill, or taking a longer detour round it.

Naismith’s Rule

Imperial  Metric
Allow one hour for every three miles walked. 

Add one hour for every 2000 ft of ascent. 

Allow one hour for every five kilometres walked. 

Add one hour for every 600 metres of ascent. 


Despite
a number of corrections that have been proposed over the years (e.g. to take into account fitness or slope gradient), Naismith’s Rule has remained a staple on navigation syllabi across the country and is still used by our digital mapping product OS Maps. Read More