Work out how long a hill walk will take, when you will finish, and how much daylight you will have left. Pick one of our hikes or enter your own route.
How It Works
Naismith's Rule
Ordnance Survey gives Naismith's rule in metric as:
- Allow 1 hour for every 5 km walked (about 3.1 miles)
- Add 1 hour for every 600 metres of ascent
Naismith's rule does not take account of how steep the ground is. Rough paths, bogs, scrambling, snow, wind, a heavy pack or a slow member of the group will all make you slower.
Pace and Breaks
Naismith's rule is a rule of thumb for a fit walker. Our pace options simply scale its walking time: Brisk takes 15% off, Steady adds 25%, Gentle adds 50% and Slow doubles it. These are our own adjustments, not part of the published rule. Time yourself on a few walks to see which suits you.
Your stops are then added on top. Be generous: lunch, photos and a slow group add up quickly.
Sunrise, Sunset and Twilight
Your browser works out the sun times for your date and place using the NOAA general solar position equations. Sunrise and sunset use the NOAA correction for the size of the sun's disc and the bending of light by the air. Times are shown in UK time. These equations are a close approximation: in our own checks against a more detailed method, they were within 4 minutes for places across Britain, so treat them as a guide.
First light and last light are the start and end of civil twilight, when the centre of the sun is 6 degrees below the horizon. The US National Weather Service says that in civil twilight the landscape can still be made out, and in many cases you can get around outdoors without a light. After that it is properly dark.
Latest Sensible Start
This is the latest time you could set off and still finish your walk, with your breaks, before your safety margin starts. We suggest finishing at least 1 hour before sunset, which leaves time for a wrong turn, a slow descent or a problem. This margin is our suggestion, not an official rule, and you can change it above.
Sources
- Ordnance Survey: Why we're adjusting Naismith's Rule (the rule in miles and in metric)
- NOAA Global Monitoring Laboratory: General Solar Position Calculations (sunrise and sunset equations)
- US National Weather Service: Twilight types (civil twilight definition)
- British Mountaineering Council: Get set for an early sunset (torches and planning for darkness)
- Hike distances, ascents and start points come from our own hike pages, and hill positions from our own hill pages. Hill heights are from the Database of British and Irish Hills.