How Long Will It Take? Pacing a Walk With Naismith's Rule

One of the most common mistakes on a day walk is underestimating how long it will take. A route that looks short on the map can feel long once you add steep climbs, rough ground and a lunch stop with a view. Fortunately, there is a simple rule of thumb that has helped walkers plan for well over a century, and it takes only a minute with a calculator.

What the rule says

Naismith's rule was devised by a Scottish mountaineer, William Naismith, in the late nineteenth century. In its original form it allowed one hour for every three miles on the flat plus an extra hour for every two thousand feet of climbing. The metric version most walkers use today is:

• Allow one hour for every five kilometres of distance.
• Add ten minutes for every hundred metres of ascent.

It gives a baseline for a fit walker moving steadily with a light pack. For many people, particularly on rough terrain, it is a minimum rather than a prediction.

A worked example

Imagine a circular walk of 12 kilometres with a total of 600 metres of climbing.

1. Distance: 12 divided by 5 gives 2.4 hours, or 2 hours 24 minutes.
2. Ascent: 600 metres is six lots of 100 metres, so six times ten minutes gives 60 minutes.
3. Total moving time: 2 hours 24 minutes plus 60 minutes is 3 hours 24 minutes.

Now add real life. A morning coffee stop, lunch, a few photographs and a bit of navigation can easily add an hour or more. A realistic plan for the day is therefore about four and a half to five hours from start to finish.

Where the rule falls short

Naismith's rule does not account for everything. Treat it as a starting point and adjust for:

• Terrain. Boggy moorland, boulder fields and loose scree are much slower than a firm track.
• Descents. Steep descents can be slow and hard on the knees, especially when wet. The simple rule ignores them.
• Weather. Strong wind, rain or snow will slow everyone down.
• Group size and ability. The pace of a group is the pace of its slowest member, and children or less experienced walkers will need more time.
• Load. A heavy pack makes the climbs harder.

Many walkers add a margin of 10 to 25 percent after calculating, then add their rest stops on top.

Use your own pace

The best correction comes from experience. On your next few walks, note the distance, ascent and your actual time. After a handful of outings you will see how closely the rule fits you. Some people find they are consistently faster, others slower, and either way you have a personal figure that is more useful than any formula.

Planning around daylight

Once you have an estimated time, work back from sunset rather than forwards from the car park. In winter, daylight is limited and an easy-looking walk can end in the dark. Set a turn-around time, a fixed point on the clock at which you head back whatever the summit looks like. It is a quiet habit that has prevented many difficult evenings. Our calm beginner's checklist for planning a day walk in the hills puts timings alongside the other planning steps.

Sharing your plan

Tell someone where you are going and when you expect to return, and keep to the plan or update them if it changes. If you will be relying on a bus or train to start or finish, build the timetable into your estimate too. Our guide to reaching trailheads without a car covers the practicalities of public transport.

Frequently asked questions

Is five kilometres an hour realistic? On flat, firm ground it is a brisk but steady pace for many adults. On rough or hilly paths, most walkers move more slowly, which is why ascent time is added.

Does the rule include breaks? No. It only estimates moving time, so add time for rests, food and photographs.

Should I use it for coastal paths? Yes, but remember that coastal paths often have many short, steep ups and downs that do not show clearly on the map. Be generous with your estimate.