What is Naismith's Rule?

Naismith's Rule, devised by Scottish mountaineer William Naismith in 1892, estimates walking time by allowing 1 hour for every 5km of horizontal distance plus 1 minute for every 10 metres of ascent. It's the standard formula used by UK hillwalkers and mountain leaders.

What are Tranter's corrections?

Tranter's corrections, developed by Philip Tranter, adjust Naismith's basic time estimate for individual fitness levels. A very fit person might complete a route in 80% of Naismith's time, while an unfit person might take 150%. The corrections also account for fatigue on longer days.

Does descent slow you down?

Gentle descents are faster than flat walking, but steep descents (over about 12 degrees or 20% gradient) actually slow you down due to the need for careful foot placement. Very steep descents on rough ground can be slower than ascending the same slope.

How accurate is this calculator?

Naismith's Rule is reasonably accurate for most UK hill conditions. The main factors that can cause variation are: boggy ground (add 25-50% time), strong headwinds (add 20-30%), poor visibility requiring navigation (add 20%), and group size (a group moves at the pace of the slowest member).

Should I add time for rest breaks?

Yes. This calculator gives walking time only. Add 5-10 minutes per hour for short rests, plus any time for lunch stops, photo stops, or navigation. A common rule is to add 10-15% to the walking time for breaks on a full day out.

CampCalcs

Naismith's Rule Calculator

Calculate hiking time using Naismith's rule with adjustments for terrain and fitness.

Distance

Distance measurement

Total Ascent

Total elevation gain

Total Descent

Enter the total descent

Fitness Level

Enter the fitness level

Pack Weight

Weight measurement

How We Calculate This

Naismith's Rule

Allow 1 hour for every 5km of horizontal distance plus 1 hour for every 600m of ascent.

Equivalently: 12 minutes per kilometre + 1 minute per 10 metres of ascent.

Adjustments Applied

Fitness multiplier (Tranter's): Very fit (0.8x), Fit (0.9x), Average (1.0x), Below average (1.2x), Unfit (1.5x)

Pack weight: None (0.95x), Light (1.0x), Medium (1.1x), Heavy (1.25x)

Steep descent: 1 minute per 20m of descent is added before multipliers.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify conditions and use proper safety equipment outdoors.