Hiking Time Calculator (Naismith Rule)
Trail time from distance and ascent with fitness adjustment and breaks.
What it does
William Naismith published his rule for Scottish hills in 1892: an hour for every five kilometers forward plus half an hour for every three hundred meters up. It survives because it reduces a route card to one addition that fits on a map margin.
The tool above applies that rule to your distance and ascent, adjusts for walking pace, adds ten minutes of short stops per hour, and prints an effort distance that compares routes at a glance.
The rule assumes a fit walker on decent paths with a day pack. Fresh legs on gravel match it well. Mud, scree, route finding, heavy packs, and altitude all slow the clock, while trail runners on smooth descents beat it.
Descent barely counts in the classic form, which regulars patch with ten minutes per three hundred meters down on steep ground. Knees and darkness argue for generous margins on the way back.
How to use
- Switch the unit system first: metric for kilometers and meters, imperial for miles and feet.
- Enter trail distance in km from the map or app.
- Enter total uphill meters from the elevation profile.
- Pick the pace that fits the group weakest walker.
- Plan daylight and turn around time off the with stops number.
Formula
- distance / 5
- Hours for the flat part at 5 km per hour.
- ascent / 600
- Hours for the climb at 600 vertical meters per hour.
- fitness
- 1.15 relaxed, 1.0 steady, 0.85 brisk.
- effort km
- Flat equivalent: 100 m of climb counts like 1 km of trail.
Tranter corrections refine the rule by fitness bands, and Langmuir adjusts for descent grade, but Naismith stays the standard first estimate that mountain leaders still teach.
Worked example
Example: 10 km with 600 m of ascent, steady pace
Day hike 10 km long, 600 m up, steady walker.
- Flat part: 10 / 5 = 2 hours.
- Climb part: 600 / 600 = 1 hour.
- Moving: (2 + 1) x 1.0 = 3 hours, shown as 3 h 00 min.
- Stops: 3 full hours x 10 min = 30 min.
- Total: 3 h 00 min + 30 min = 3 h 30 min.
- Effort: 10 + 600/100 = 16 effort-km.
Reference table
| Route | Moving | With stops |
|---|---|---|
| 5 km flat | 1 h 00 min | 1 h 10 min |
| 10 km, 300 m up | 2 h 30 min | 2 h 50 min |
| 10 km, 600 m up | 3 h 00 min | 3 h 30 min |
| 15 km, 900 m up | 4 h 30 min | 5 h 10 min |
| 20 km, 1200 m up | 6 h 00 min | 7 h 00 min |
Limits
- Fit walker baseline. Groups move at the slowest member pace.
- Ground quality ignored. Bog, snow, and scree add heavily.
- No descent penalty in the classic form. Steep downhills cost knees and time.
- Weather, navigation stops, and lunch sit outside the moving math.
Common mistakes
- Counting peak height instead of total uphill from the profile.
- Planning on moving time with no stops, food, or photos.
- Letting the fastest walker set a pace the group cannot hold.
- Forgetting daylight. Start with the with stops number, not the moving one.
- Ignoring descent. Downhill kilometers still take most of flat time.
Try it yourself
Quick checks. Answers sit tucked under each question.
8 km with 400 m ascent, steady. Moving time?
8/5 + 400/600 = 1.6 + 0.67 = 2.27 h, about 2 h 16 min.
With stops for that hike?
Two full hours give 20 min of stops: 2 h 16 min + 20 min = 2 h 36 min.
Questions
What is Naismith rule exactly?
One hour per 5 km forward plus 30 minutes per 300 m of ascent, from an 1892 Scottish mountaineering paper.
Does it work for running?
No, it fits walking. Trail pace charts and race predictors serve runners better.
How do I count ascent?
Add every uphill section from the elevation profile. Rolling routes accumulate more than the summit height.
What about steep descents?
Allow roughly 10 minutes per 300 m down on steep ground, plus care for knees.
How much water per hour hiking?
About half a liter per hour in normal weather, more in heat. Carry plus a reserve.
When should I turn back?
Set the time before starting, usually two thirds of daylight, and honor it regardless of the summit.