About
Effortlessly plan your hiking adventures with my user-friendly Naismith's Rule calculator.
The calculator provides accurate hiking time estimates based on distance, elevation (climb and descent), and the grade of the track.
What is Naismith's Rule
Naismith's Rule, originally devised by Scottish mountaineer William W. Naismith in 1892, is a valuable guideline for estimating the time required to complete a walking or hiking expedition. It considers both the horizontal distance traveled and the vertical ascent to provide a more accurate estimate of the journey's duration. This rule of thumb has been invaluable to hikers, mountaineers, and outdoor enthusiasts for more than a century.
The original formulation of Naismith's Rule advised allowing one hour for every three miles (approximately 5 kilometers) of horizontal distance, in addition to an extra hour for every 2,000 feet (around 600 meters) of vertical ascent. This approach provides a straightforward way to account for the additional effort and time required to travel uphill, which is generally more demanding than walking on level terrain. Over the years, refinements to Naismith's Rule have been introduced to account for variations in individual fitness levels, terrain, and hiking conditions.
It is essential to remember that Naismith's Rule is a guideline, not a definitive predictor of hiking time. The actual time required for a specific hike may vary due to factors such as weather conditions, individual fitness and experience, and the weight of the backpack being carried. However, Naismith's Rule remains a helpful tool for planning and preparing for outdoor adventures, allowing hikers to estimate the time required for their journey and make informed decisions about their route, equipment, and supplies.
Improving on Naismith's Rule
The original formula developed by Naismith was a useful tool for calculating the time needed to traverse a given distance, taking into account only horizontal distance and ascent. However, in order to make the formula more accurate and applicable to a wider range of terrains, my improved calculator introduces two additional variables - descent and the grade of the terrain.
The descent formula is based on the work of Eric Langmuir, who proposed a refinement in 1984 by subtracting 10 minutes for every 300 meters of descent on a gentle slope. This adjustment accounts for the additional time and effort required to descend a slope, which is often overlooked in the original formula.
In addition to descent, my calculator also incorporates a five-step scale for the roughness of terrain (or grade), ranging from a light and easy-going vehicle track to thick and heavy-going bush. Each step on the scale assumes a different relationship with the original Naismith formula, with the easiest terrain maintaining a 1:1 relationship of 5 km/h and the most difficult terrain reducing the horizontal distance time down to just 0.5 km/h.
The calculations for each of the five steps were derived through on-ground hiking in the Australian bush, involving hundreds of kilometers of hikes in all weather conditions and track grades. This ensured that the formula was as accurate and reliable as possible, and can be used with confidence by hikers, climbers, and other outdoor enthusiasts.
Who developed this hiking calculator
Over the course of several years, James Robinson developed both the calculator and the formulas that power it. As a Scout Leader at 1st Blackheath Scout Group, James frequently embarks on hikes into the rugged wilderness of the upper Blue Mountains, located just west of Sydney, Australia. In the remote Australian bush, detailed planning of hikes and expeditions is essential for safety and survival. Thus, a user-friendly calculator to help determine projected travel times for each leg of a journey is a crucial tool.