What is Naismith's Rule?

Naismith's Rule is a time-honored formula developed by Scottish mountaineer William Naismith in 1892 for estimating hiking time. The formula is: time (hours) = distance (km) / 5 + elevation (m) / 600. It assumes an average walking speed of 5 km/h (3.1 mph) on flat ground, with 1 hour added for every 600 meters (1,970 feet) of elevation gain. This rule has been used by hikers and mountaineers for over a century as a baseline for trip planning.

How accurate is this estimate?

Naismith's Rule provides a reasonable baseline for average hikers on moderate terrain, but actual times can vary significantly. Factors that affect accuracy include: individual fitness (experienced hikers may be 20-30% faster), terrain difficulty (rocky or technical terrain slows progress), weather conditions (rain, snow, wind), pack weight (heavy packs reduce speed), and rest breaks. Always add a 20-50% safety buffer, especially for longer hikes or difficult conditions.

Should I adjust for downhill sections?

Naismith's Rule only accounts for elevation gain, not loss. While downhill hiking can be faster on gentle slopes, steep descents can actually be slower and more tiring than uphill sections. For very steep descents (over 30°), you might add time rather than subtract it. The rule works best when elevation gain is the primary factor. For routes with significant elevation loss, consider that descents may take 70-90% of the time that equivalent ascents would take.

How do I account for rest breaks?

Naismith's Rule doesn't include rest breaks, so you need to add them separately. Plan for 5-10 minutes of rest per hour of hiking time. For a 4-hour hike, add 20-40 minutes for breaks. Longer hikes may need more frequent or longer breaks. Also account for lunch stops (30-60 minutes) and photo stops. A good rule of thumb: add 10-15% to your total time for breaks on day hikes, and 15-20% for longer backpacking trips.

Does this work for trail running?

No, Naismith's Rule is designed for hiking/walking pace. Trail runners move much faster - typically 8-12 km/h on flat ground and 5-8 km/h on moderate uphills. For trail running estimates, you might use: time = distance / 8 + elevation / 400 (for moderate pace) or distance / 10 + elevation / 500 (for faster pace). However, trail running times vary even more than hiking based on fitness and terrain.

How should I adjust for group hiking?

When hiking in a group, plan for the pace of the slowest member. Groups typically move 10-20% slower than individuals due to coordination, conversation, and waiting. Larger groups (6+ people) may be even slower. Plan extra time for group breaks and decision-making. It's often better to split into smaller groups with similar fitness levels if possible. Always ensure the slowest member is comfortable with the pace and route.

Hiking Time Estimator

Estimate hike duration using Naismith's Rule based on distance and elevation.

Distance (km)

Elevation Gain (meters)

How This Tool Works

This calculator uses Naismith's Rule, a time-honored formula developed by Scottish mountaineer William Naismith in 1892. The rule estimates hiking time based on distance and elevation gain, assuming an average walking speed of 5 km/h (3.1 mph) on flat ground, with an additional hour added for every 600 meters (1,970 feet) of elevation gain. This formula has been used by hikers, mountaineers, and outdoor enthusiasts for over a century as a reliable baseline for trip planning and route estimation.

While Naismith's Rule provides a useful baseline, actual hiking times can vary significantly based on individual fitness, terrain difficulty, weather conditions, pack weight, rest breaks, and group pace. The rule works best for moderate terrain and average fitness levels. Always add a safety buffer (20-50%) to account for unexpected delays, difficult terrain, or slower group members. The calculator accounts for the mathematical relationship between distance and elevation, but real-world factors like trail conditions, weather, and personal fitness can significantly impact actual hiking times.

Formula

Naismith's Rule formula:

Time (hours) = Distance (km) / 5 + Elevation (m) / 600

Examples

10km, 500m elevation: ~2.8 hours (10/5 + 500/600 = 2 + 0.83)
5km, 300m elevation: ~1.5 hours (5/5 + 300/600 = 1 + 0.5)
15km, 1000m elevation: ~4.7 hours (15/5 + 1000/600 = 3 + 1.67)
8km, 200m elevation: ~1.9 hours (8/5 + 200/600 = 1.6 + 0.33)
20km, 0m elevation (flat): ~4 hours (20/5 + 0/600 = 4)

Factors That Affect Hiking Time

Fitness Level: Experienced hikers may be 20-30% faster, beginners 20-30% slower
Terrain: Rocky, muddy, or off-trail terrain significantly slows progress
Pack Weight: Heavy packs (20kg+) can reduce speed by 15-25%
Weather: Rain, snow, wind, and extreme temperatures slow hiking significantly
Group Size: Larger groups move at the pace of the slowest member
Rest Breaks: Frequent breaks add time - plan for 5-10 minutes per hour
Trail Conditions: Well-maintained trails are faster than overgrown or technical routes
Time of Day: Fatigue increases throughout the day, slowing afternoon progress

Planning Tips

Always add a 20-50% safety buffer to Naismith's estimate for unexpected delays
Plan to finish well before sunset - start early, especially for longer hikes
Account for rest breaks: add 5-10 minutes per hour of hiking time
Consider the slowest member of your group when planning group hikes
Check trail conditions and weather forecasts - adjust estimates accordingly
For difficult terrain, multiply the base time by 1.5-2x
Track your actual times to learn your personal pace for future planning
Remember: it's better to overestimate time than to be caught in the dark

FAQ

What is Naismith's Rule?
Naismith's Rule is a time-honored formula developed by Scottish mountaineer William Naismith in 1892 for estimating hiking time. The formula is: time (hours) = distance (km) / 5 + elevation (m) / 600. It assumes an average walking speed of 5 km/h (3.1 mph) on flat ground, with 1 hour added for every 600 meters (1,970 feet) of elevation gain. This rule has been used by hikers and mountaineers for over a century as a baseline for trip planning.
How accurate is this estimate?
Naismith's Rule provides a reasonable baseline for average hikers on moderate terrain, but actual times can vary significantly. Factors that affect accuracy include: individual fitness (experienced hikers may be 20-30% faster), terrain difficulty (rocky or technical terrain slows progress), weather conditions (rain, snow, wind), pack weight (heavy packs reduce speed), and rest breaks. Always add a 20-50% safety buffer, especially for longer hikes or difficult conditions.
Should I adjust for downhill sections?
Naismith's Rule only accounts for elevation gain, not loss. While downhill hiking can be faster on gentle slopes, steep descents can actually be slower and more tiring than uphill sections. For very steep descents (over 30°), you might add time rather than subtract it. The rule works best when elevation gain is the primary factor. For routes with significant elevation loss, consider that descents may take 70-90% of the time that equivalent ascents would take.
How do I account for rest breaks?
Naismith's Rule doesn't include rest breaks, so you need to add them separately. Plan for 5-10 minutes of rest per hour of hiking time. For a 4-hour hike, add 20-40 minutes for breaks. Longer hikes may need more frequent or longer breaks. Also account for lunch stops (30-60 minutes) and photo stops. A good rule of thumb: add 10-15% to your total time for breaks on day hikes, and 15-20% for longer backpacking trips.
Does this work for trail running?
No, Naismith's Rule is designed for hiking/walking pace. Trail runners move much faster - typically 8-12 km/h on flat ground and 5-8 km/h on moderate uphills. For trail running estimates, you might use: time = distance / 8 + elevation / 400 (for moderate pace) or distance / 10 + elevation / 500 (for faster pace). However, trail running times vary even more than hiking based on fitness and terrain.
How should I adjust for group hiking?
When hiking in a group, plan for the pace of the slowest member. Groups typically move 10-20% slower than individuals due to coordination, conversation, and waiting. Larger groups (6+ people) may be even slower. Plan extra time for group breaks and decision-making. It's often better to split into smaller groups with similar fitness levels if possible. Always ensure the slowest member is comfortable with the pace and route.