Ever set off on a hike thinking “This’ll take a couple of hours,” only to find yourself racing against sunset six hours later? We’ve all been there. The good news is that there’s a brilliantly simple formula that’s been helping hikers plan their walking times for over 130 years. Meet Naismith’s Rule—your secret weapon for accurate route planning.
Whether you’re tackling Wainwright peaks, planning a coastal path adventure, or just want to know when you’ll be back for tea, understanding Naismith’s Rule will transform how you plan your walks. Let’s dive in.
What is Naismith’s Rule?
Naismith’s Rule is a straightforward formula for calculating how long a walk will take based on distance and elevation gain. It was created in 1892 by William W. Naismith, a Scottish mountaineer who was one of the founding members of the Scottish Mountaineering Club.
After a solo walk in the Scottish Highlands covering Cruach Ardrain, Stob Binnein, and Ben More, Naismith noticed his timing matched a simple pattern. He wrote in the Scottish Mountaineering Club Journal: “an hour for every three miles on the map, with an additional hour for every 2,000 feet of ascent.”
That’s it. Simple, elegant, and remarkably accurate for over a century.
The Basic Formula
The modern version of Naismith’s Rule works like this:
Standard Naismith’s Rule:
- Allow 1 hour for every 5 kilometres (or 3 miles) of distance
- Add 1 hour for every 600 metres (or 2,000 feet) of ascent
This assumes you’re a reasonably fit walker on typical terrain under normal conditions. Think clear paths, decent weather, and no major navigational challenges.
Quick Example
Let’s say you’re planning a Lake District walk that’s 10km with 900m of ascent:
- Distance time: 10km ÷ 5 = 2 hours
- Ascent time: 900m ÷ 600 = 1.5 hours
- Total estimated time: 3.5 hours
Job done. You now have a baseline estimate for your walking time.
Why Does Naismith’s Rule Work?
The beauty of Naismith’s Rule is that it recognises a fundamental truth about hill walking: going uphill slows you down significantly. On the flat, most people maintain a steady pace of around 5km/h (or about 12 minutes per kilometre). But start climbing, and that pace drops dramatically.
Naismith worked out that every 100 metres of ascent takes roughly the same time as walking 1 kilometre on the flat. This equivalence between distance and elevation is what makes the rule so useful for mountain and fell walking.
Studies have shown Naismith’s Rule to be remarkably accurate—one analysis of 124 hikes found it predicted times correctly 81% of the time, which is pretty impressive for a formula devised before cars were common.
When to Use Naismith’s Rule
Naismith’s Rule is perfect for:
- Lake District fell walks and Wainwright bagging—ideal for those undulating mountain routes
- Hill walking and mountain hiking anywhere in the UK
- Route planning when you need to estimate total walk duration
- Group walks where you need to set realistic timings
- Day hike planning to ensure you’re back before dark
It’s less useful for:
- Scrambling or technical climbing routes
- Very flat terrain (though it still works, just seems overkill)
- Ultra-steep descents where you need to go carefully
Adjusting Naismith’s Rule for Real-World Conditions
Here’s where it gets interesting. Basic Naismith gives you a minimum time, but real walks involve more variables. Over the years, experienced walkers have refined the rule with various corrections:
1. Terrain Factor
Not all paths are created equal:
- Easy tracks and roads: Use 90% of calculated time (multiply by 0.9)
- Typical paths: Use the standard calculation (multiply by 1.0)
- Rough, uneven ground: Add 10% (multiply by 1.1)
- Very rough terrain, scree, or heathland: Add 20% (multiply by 1.2)
2. Descent Time
Naismith’s original rule didn’t account for going downhill. Modern adaptations suggest:
- Gentle descent (5-12°): Subtract 10 minutes per 300m descent
- Steep descent (over 12°): Add 10 minutes per 300m descent (yes, add—steep descents are slow and tiring)
3. Fitness Level
Be honest with yourself:
- Very fit hill walkers: Use the standard formula, or even slightly less
- Average fitness: Add 25% to your calculated time
- Less experienced or carrying heavy loads: Add 50%
4. Group Walking
Always plan for the slowest member of your group. The rule of thumb? Add 15 minutes per person to account for different paces and more frequent stops.
5. Rest Time
Don’t forget to factor in breaks! Add time for:
- Lunch stops (20-30 minutes)
- Photo opportunities on those stunning summits
- Map checks and navigation
- Catching your breath on steep sections
A good rule is to add 10-15 minutes per hour of walking for shorter breaks and navigation.
Practical Example: Planning a Wainwright Walk
Let’s plan a classic Lake District walk—Helvellyn via Striding Edge from Glenridding:
Route Stats:
- Distance: 14.5km
- Ascent: 950m
- Descent: 950m
- Terrain: Mix of paths and rocky sections
Basic Naismith Calculation:
- Distance time: 14.5km ÷ 5 = 2.9 hours
- Ascent time: 950m ÷ 600 = 1.6 hours
- Basic total: 4.5 hours
Adjustments:
- Terrain factor (slightly rough): 4.5 × 1.1 = 5 hours
- Descent adjustment (moderate, some steep): +20 minutes
- Rest/navigation time: +45 minutes
- Realistic total: 6 hours
And there you have it—a realistic time estimate that accounts for the actual conditions you’ll face on the hill.
Using Our Naismith Calculator
While it’s good to understand the maths, there’s no need to do it all manually. We’ve built a free Naismith’s Rule calculator right here on Out and About that does all the heavy lifting for you.
Our calculator lets you:
- Input distance in kilometres or miles
- Add ascent and descent in metres or feet
- Adjust for terrain difficulty
- Factor in your personal walking speed
- Include rest time
- Share your calculations via URL
It’s particularly handy when you’re planning Wainwright walks or any Lake District routes where elevation plays a big role. Just plug in your numbers, and you’ll get an instant time estimate broken down by distance, ascent, and any adjustments you’ve made.
Common Mistakes to Avoid
Being Too Optimistic
Naismith’s Rule gives you the minimum time for “men in fair condition” (as he put it in 1892). Most of us need to add at least 25% for a realistic estimate. Remember, it’s always better to finish early than to be caught out after dark.
Forgetting About Descent
Going down steep, rocky paths can be slower than going up. If your route involves technical descents, add time rather than assuming you’ll fly down.
Ignoring Terrain
There’s a massive difference between walking on a well-maintained path and pushing through boggy moorland or picking your way across scree. Always factor in terrain difficulty.
Not Planning for Breaks
You will stop. You’ll want to admire the view, check your map, catch your breath, and eat your sandwiches. Build this time in from the start.
Using it for Easy, Flat Walks
On canal towpaths or coastal walks with minimal elevation, Naismith’s Rule is overkill. Just use distance divided by your normal walking pace (usually 4-5 km/h for leisure walking).
Tips for Better Time Estimates
Track Your Own Pace
Use a GPS watch or hiking app to record a few walks and see how your actual times compare to Naismith’s estimates. You might find you naturally walk faster or slower than the standard 5km/h.
Check the Weather Forecast
Strong winds, driving rain, or heavy snow will slow you down significantly. In poor conditions, add at least 25-50% to your estimated time.
Be Honest About Fitness
If you haven’t been out walking for a while, or you’re carrying a heavy pack, you’ll be slower. That’s fine—just plan accordingly.
Start a Walking Journal
Note down your estimated times versus actual times for different types of walks. You’ll quickly build up a personal database of what works for you.
Beyond Basic Naismith: Modern Alternatives
While Naismith’s Rule remains the gold standard for UK hill walking, other formulas have been developed:
Tobler’s Hiking Function
A more complex formula that accounts for both uphill and downhill gradients, predicting maximum speed on a gentle downslope of about 5%. Popular among scientific researchers but less practical for everyday use.
Langmuir Corrections
Specific adjustments for different descent angles, widely used in UK mountain rescue and outdoor education.
Tranter Corrections
Adjusts for fitness levels by using a table that compares your fitness to the standard Naismith walker.
Honestly? For most walkers, basic Naismith with sensible real-world adjustments is more than adequate. Don’t overthink it.
Putting It All Together: Your Walking Time Checklist
Here’s a quick checklist for planning any walk:
- Measure your route using a map, GPS device, or our route maps
- Note the total ascent (and significant descent if applicable)
- Apply basic Naismith’s Rule (1 hour per 5km + 1 hour per 600m ascent)
- Adjust for terrain (multiply by 0.9-1.2 depending on conditions)
- Add descent time if your route includes steep downhills
- Factor in rest time (at least 10-15 minutes per hour of walking)
- Consider your fitness and add 25-50% if you’re being realistic
- Plan for the slowest person if walking in a group
- Check the weather and add extra time for poor conditions
- Add a buffer of at least 30-60 minutes for unexpected delays
Final Thoughts
Naismith’s Rule isn’t perfect—no formula can account for every variable on every walk. But it’s a remarkably good starting point that’s stood the test of time for over 130 years. Combined with a bit of common sense and personal experience, it’ll help you plan walks that are challenging but achievable, with enough time built in to actually enjoy the experience rather than constantly watching the clock.
The key is to use it as a guide, not gospel. Track your own walking times, adjust for your fitness and conditions, and always err on the side of caution. It’s far better to finish a walk with time to spare than to be racing sunset down a mountain path.
So next time you’re planning a Lake District Wainwright, a coastal path adventure, or any UK hill walk, give Naismith’s Rule a go. Your future self—the one not stumbling down a fell in the dark—will thank you.
Happy walking, and remember: it’s not just about the destination, it’s about having enough time to enjoy the journey!
Ready to Plan Your Next Walk?
Use our free Naismith Calculator to estimate your walking times in seconds. Factor in distance, ascent, terrain, and personal pace for accurate planning.
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