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Naismith rule calculator

Horizontal time plus time for ascent

Naismith’s rule is a nineteenth-century way to budget walking time in the hills. W. W. Naismith’s version, published in the Scottish Mountaineering Club Journal in 1892, allows time for the horizontal distance and extra time for climbing. The form used here is the widely repeated one: about 3 miles per hour on the flat, plus 1 hour for every 2,000 feet of ascent, which is 30 minutes per 1,000 feet. Both numbers are editable, because the rule is a starting point, not a personal pace.

Inputs

Result

Enter distance and ascent.

Disclaimer: A planning rule of thumb, not a prediction. Fatigue, pack weight, trail surface, and stops can dominate the result. It is not a safety guarantee.

Weather changes the day even when the time budget is right. Check feels-like temperature on the ClearQuip wind chill and heat index calculator.

How to use

  1. Enter the map distance and whether it is in miles or kilometers.
  2. Leave horizontal speed at 3 if you want the classic rule and your distance is in miles. If the distance is in kilometers, the matching classic speed is about 5 km/h; type 5 and keep the distance unit on kilometers.
  3. Enter the ascent. The extra minutes are always per 1,000 feet after any meter conversion.
  4. Press Calculate. The total is horizontal time plus ascent time. Reset restores the classic defaults.

How it's calculated

Horizontal hours = distance ÷ speed
Ascent hours = (ascent in feet ÷ 1,000) × (minutes per 1,000 ft ÷ 60)
Total = horizontal + ascent

The classic pair is 3 miles per hour and 30 minutes per 1,000 feet. Thirty minutes per 1,000 feet is the same as one hour per 2,000 feet. Descent is not given extra time in Naismith’s original allowance; steep descents can be slower than the flat rate anyway, and this page does not add a descent penalty unless you lower the horizontal speed yourself.

If you already know your own pace and there is little climb, the pace calculator is the more direct tool. Cumulative ascent from a list of elevations is the elevation gain calculator; paste its gain into the ascent field here.

Worked example

Six miles and 2,000 feet of ascent at the classic settings: horizontal time is 6 ÷ 3 = 2 hours. Ascent time is 2,000 ÷ 1,000 × 30 minutes = 60 minutes. The estimate is 3 hours of moving time. The same 6 miles with no climb is 2 hours. A fitter or slower party changes the speed or the minutes-per-thousand field; the page does not pick a fitness score for you.

Assumptions and sources

Naismith described the allowance in the Scottish Mountaineering Club Journal in 1892. The 3 mph and 1 hour per 2,000 feet form is the version commonly restated in hiking references. Later corrections, such as Tranter’s, adjust for fitness using a table this page does not reproduce. The calculator converts kilometers to miles with 1.609344 and meters to feet with 0.3048 meters per foot before it applies the per-1,000-feet rate.

FAQ

Does Naismith include breaks?

No. It is a moving-time allowance. Add breaks on top if you want a clock time.

What about downhill?

The original rule does not add time for descent. Very steep or loose descents are often slower than 3 mph. Lower the horizontal speed if that matches the trail.

Why is the default 30 minutes per 1,000 feet?

Because 1 hour per 2,000 feet is 30 minutes per 1,000 feet. You can replace 30 with another number.

Is 5 kilometers per hour the same idea as 3 miles per hour?

They are close. Three miles is 4.83 kilometers, so 3 mph is about 4.8 km/h. People often round the metric statement of the rule to 5 km/h plus 1 hour per 600 meters of ascent. Use the defaults that match the units you entered.

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