Outdoors / Walking
Hiking Time Calculator (Naismith's Rule and Tobler's Function)
Estimate how long a walk or hike will take from its distance, total ascent, and descent, by Naismith's rule with Langmuir's descent allowance and by Tobler's hiking function, adding time for breaks, in km and metres or miles and feet.
Hiking Time Calculator (Naismith's Rule and Tobler's Function): Naismith's rule allows an hour for every 5 km plus an hour for every 600 m climbed: 12 km with 800 m of ascent is 3 hours 44 minutes of walking. Langmuir's correction adds 10 minutes for every 300 m of descent. Tobler's function sets the speed by the slope, about 5 km/h on the flat and fastest on a gentle downhill, with the distance split between the climbing and descending parts. Runs 100% locally in your browser with zero server file uploads.
- Category
- Everyday tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Naismith's rule, from 1892, allows an hour for every 5 km (3 miles) plus an hour for every 600 m (2,000 ft) of ascent; Langmuir added 10 minutes for every 300 m of steady descent. Tobler's function gives a walking speed for each slope, fastest on a gentle downhill. Both assume fit walkers on good paths with light packs: allow more for rough ground, heavy loads, snow, children, and darkness, and plan to finish well before sunset.
Example
A 12 km circuit with 800 m up and down: Naismith gives 2 h 24 min for the distance plus 1 h 20 min for the climb, 3 h 44 min; Langmuir adds 27 minutes for the descent; with 45 minutes of breaks, plan on about 4½ to 5 hours.
Daylight
Start early enough to finish with time to spare before dark; the sunrise and sunset calculator gives the times for any place and date.
How to use it
- Enter the distance and the total ascent and descent from your map or app.
- Add the time you plan for breaks.
- Compare the three estimates, and allow extra for rough ground and slower walkers.
Privacy & limitations
Everything is calculated in your browser.
Related tools
Frequently asked questions
Which estimate should I trust?
Naismith's rule is the classic planning figure for fit walkers; Tobler's is often quicker on steady slopes. Compare both with your own past walks and adjust.
Do the rules allow for breaks?
No: they give moving time, which is why breaks are added separately.
Where do I find the total ascent?
Route planning apps and many guidebooks give it; on a paper map, add up the contour lines you climb.
Free tool · runs in your browser · no account required