How to use
- 1Choose the method (Naismith or DIN 33466) and units — miles/feet or km/metres.
- 2Enter distance, total ascent and total descent from your map, route planner or GPS track.
- 3For Naismith, set the descent type and, if you like, a Tranter fitness level or group pace.
- 4Add break minutes per hour walked and your start time to see total time, arrival time and average speed.
The rules behind the numbers
Naismith’s rule allows 5 km/h on the flat plus 1 hour per 600 m of ascent — in imperial, 3 mph plus 1 hour per 2,000 ft. Langmuir’s correction adjusts for descent: take off 10 minutes per 300 m on gentle slopes (5–12°) and add 10 minutes per 300 m on steep ground over 12°; “half and half” cancels out. Langmuir’s group pace (4 km/h plus 1 hour per 450 m) suits mixed-ability parties. DIN 33466, used for Alpine club signposts, works out horizontal time at 4 km/h and vertical time at 300 m/h up and 500 m/h down, then adds half the smaller to the larger.
Choosing your Tranter fitness level
Tranter’s corrections scale the time to your fitness, defined as the minutes you need to climb 300 m over 800 m of distance. Time yourself on a familiar hill: 15 minutes is very fit, 25–30 is typical, 40–50 is a slow pace. On long days the table runs out for the lower fitness levels and the calculator shows “too long” — a sign to split the route or start much earlier.
Planning UK hill days and US trails
Mountain Training courses and DofE expedition groups commonly plan legs with Naismith plus Langmuir, and group pace is a sensible choice for teenagers carrying full packs. On US trails, where guides quote miles and feet of elevation gain, switch to imperial units. Either way the result is an estimate: weather, terrain, pack weight and navigation all change your pace, so check the forecast, compare the arrival time with sunset and keep a margin for the descent.
Frequently asked questions
What is Naismith’s rule?
A rule of thumb from 1892: allow 1 hour for every 5 km (3 miles) on the flat plus 1 hour for every 600 m (2,000 ft) of ascent.
How long does it take to hike 10 miles?
On flat ground about 3 h 20 min by Naismith. Each 2,000 ft of climbing adds an hour, plus whatever breaks you take.
Does Naismith’s rule include breaks?
No, it gives moving time only. Enter break minutes per hour walked in the calculator to get total time and arrival.
Why are signpost times in the Alps different?
Alpine club signposts use DIN 33466, which assumes 4 km/h and counts descent as well as ascent, so its times differ from Naismith.
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