Hiking Time Calculator

Naismith’s Rule is the standard hiking time formula developed by Scottish mountaineer William Naismith in 1892. It estimates total walking time based on horizontal distance and elevation gain, and has been validated for over 130 years of practical use.

Naismith’s Rule formula: Time = (Distance ÷ Pace) + (Elevation Gain ÷ Climb Rate)

Standard values:

• Pace = 5 km/h (3.1 mph) on flat terrain
• Climb Rate = 600 m/hr (2,000 ft/hr) for elevation gain

Full formula with standard values: Time (hours) = (Distance in km ÷ 5) + (Elevation Gain in meters ÷ 600)

Tobler’s Hiking Function (modern refinement): Adjusts pace for slope angle: Speed = 6 × exp(−3.5 × |slope + 0.05|) km/h

Where slope = rise/run (tangent of grade angle). Tobler is not what this page uses; Naismith with the corrections below is close enough on a real trail and far easier to sanity-check.

Corrections to Naismith’s Rule, all four of which this calculator applies:

• Steep descent: add 1 hour per 1,500 m (5,000 ft) of descent. Gentle downhill is faster than flat and needs no correction
• Pack weight: 7 to 15 kg adds about 15%, over 15 kg about 25%
• Trail conditions (mud, snow, scree, rock): add 25 to 50%
• Fitness: the “Fit” setting is Naismith’s own 5 km/h. Beginners walk closer to 2.5 km/h once a trail turns rough

What each variable means:

• Horizontal distance is trail distance, not straight-line distance on a map
• Elevation gain is total uphill, not net. A trail that goes up 500 m, down 200 m, then up 300 m has gained 800 m, not 600
• Rest stops are excluded from Naismith’s figure. Add 10 minutes per hour of walking
• Steep descent is only the genuinely steep part. Do not enter the whole downhill leg of a there-and-back

Worked example: Trail: 18 km distance, 900 m elevation gain, a fit party carrying day packs on a dry trail.

• Walking = 18 ÷ 5 = 3.60 hours
• Climbing = 900 ÷ 600 = 1.50 hours
• Base = 5.10 hours, which is 5 hours 6 minutes of moving time
• Rest at 10 min per hour = 5.10 × 1.1667 = 5.95 hours, or 5 hours 57 minutes

Want to be back at the car by 4:00 PM? Leave the trailhead by 10:03 AM, and earlier than that if the forecast is poor or anyone in the group is slower than the rest. The party moves at the pace of its slowest member, which is the single correction no formula can make for you.