> Allow one hour for every 3 miles (5 km) forward, plus an additional hour for every 2,000 feet (600 m) of ascent.<p>> In practice, the results of Naismith's rule are usually considered the minimum time necessary to complete a route.<p>Yup that seems like a pretty aggressive estimation to me. Maybe doable by very fit hikers if they make a concerted effort. But not leaving any margin for error, lunch, taking photos, etc.<p>For perspective I recently did a 13.5 km hike with 1800m climbing in 6.5 hours. This was a training hike, so there was very little stopping time, and I passed a lot of people along the way (and was only passed by one or two trail runners). The trail was also very well maintained. According to Naismith’s Rule it should have taken 5.7 hours. (Possibly because it’s not accounting for the 1800m of descent, which I feel is slower than walking on flat terrain when it’s sufficiently steep).<p>I tend to just go with whatever times the map/information guide lists. Typically they are very conservative and allow far more time than we need - but worst case scenario is you can just spend more time at camp, take a scenic diversion, eat a long lunch, etc. Or get back to the car early and go find a hot spring to soak in. Much better than the alternative of not leaving enough time and having to hike through an unfamiliar location in the dark.
Tobler's hiking function [<a href="https://en.m.wikipedia.org/wiki/Tobler%27s_hiking_function" rel="nofollow">https://en.m.wikipedia.org/wiki/Tobler%27s_hiking_function</a>] linked in the 'See also' section is also very interesting. E.g., says that maximum speed is around 2 degrees sloping downwards and that speed comes down to about a tenth at around 30-40 degrees slope upwards or downwards.
Works for cycling too -- I can estimate at ~ 15mph + 30min/1000ft of climbing for long rides.<p>The hour for 2000ft of ascent works out to 1.6 w/kg for just vertical potential energy -- that's in the reasonably fit adult range, not elite athlete.
Wow, 5km/h is very fast for any kind of loaded hiking. That's about the speed I walk to the shops when not carrying anything.<p>The more useful part of this is the 1:8 ratio. Every 125m of climbing is equivalent to 1km of horizontal.
IME, it's also a pretty good estimate of <i>urban</i> 3-mile walking, at a typical adult pace.<p>Sidewalks are easier than dirt trails, but add significant time waiting to cross some streets.
Naismith's rule helps with the planning of a walking or hiking expedition by calculating how long it will take to travel the intended route, including any extra time taken when walking uphill. This rule of thumb was devised by William W. Naismith, a Scottish mountaineer, in 1892. A modern version can be formulated as follows:<p>Allow one hour for every 3 miles (5 km) forward, plus an additional hour for every 2,000 feet (600 m) of ascent.