What is Naismith’s Rule?

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What is Naismith’s Rule?

Many of you have heard of Naismith’s Rule, but what is Naismith’s Rule and how do you work it out?

This rule of thumb was devised by William W. Naismith, a Scottish mountaineer, in 1892

Naismith’s Rule has remained a staple on navigation syllabi across the country and is still used to this day, but what is it?

Part of its enduring appeal no doubt stems from its simplicity – a rule of thumb that can be employed with minimal mental strain is a great asset when navigating.

Naismith’s Rule


Allow one hour for every three miles walked.
Add one hour for every 2,000 ft of ascent.


Allow one hour for every five kilometres walked.
Add an hour for every 600 metres of ascent.

This rule is a simple approximation and assumes ideal conditions.

In the GPS Training free route planner it automatically calculates the time your planned walk will take you using Naismith’s Rule, the video below takes you through how you can do this.

Further reading

1. GPS Training free OS route planning software

2. GPS Training online resource - free course to improve your map and compass skills

3. Safety in the hills - keypoints

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