Baseline: 5 km/h on flat + 10 min per 100 m ascent. Adjust for terrain, descent and rest. Your inputs are saved in the URL for easy sharing.
Naismith's Rule was devised by Scottish mountaineer William Naismith in 1892. The original rule is simple: allow one hour for every 5 km of distance, plus an additional hour for every 600 m of ascent. This calculator uses the more commonly cited 10 minutes per 100 m of ascent, which is equivalent.
It is a guide, not a guarantee. Experienced fell walkers often find they move faster; beginners, large groups, or very rough terrain will be slower. Always add buffer time, particularly in the Lake District where paths and conditions can change quickly.
The original rule makes no allowance for descent or rough terrain. The terrain multiplier accounts for the extra time taken on heather, scree, or boggy ground. A value of 1.2 is appropriate for most Lake District fell routes off the main paths.
The descent penalty option follows Tranter's corrections, which add time for steep downhills on tired legs. For most walkers on typical Lake District descents, 5 minutes per 100 m is a reasonable starting point.
Accurate timing is only part of planning a safe day on the hills. Good navigation is essential on any serious walk. Always carry the right map for your area and a reliable compass. Do not rely solely on phone GPS in remote or upland terrain — batteries drain, signal fails, and screens are hard to read in poor weather.
For a comfortable day out, a well-fitted day pack, good trail shoes or boots, a lightweight waterproof jacket and trekking poles will serve you well on longer routes. For Lake District walking in particular, check out the 51 Wainwright Walks collection with GPX downloads and estimated times already calculated.
As an Amazon Associate I earn from qualifying purchases at no extra cost to you.