Walking Time Calculator

How long will my walk take?

The honest answer is: longer than distance alone suggests. A 10 km stroll along a canal towpath and a 10 km round of a Lakeland fell are completely different days out, because climbing costs time — and so, on steep ground, does coming back down. That's why walkers, Duke of Edinburgh groups and mountain leaders in the UK have used rules of thumb like Naismith's rule for more than a century.

This calculator combines those rules with the things that actually decide your day: your own pace, the terrain, how long you stop for, and when the sun sets. Enter your route's total distance, ascent and descent, split it into legs, or upload a GPX file to have every uphill, flat and downhill stretch measured for you.

Naismith's rule explained

In 1892 Scottish mountaineer William Naismith suggested allowing one hour for every 3 miles (5 km) forward, plus an hour for every 2,000 feet (600 m) of ascent. In metric that's the easy-to-remember 12 minutes per km plus 1 minute per 10 m of climbing. The UK's adventure activities licensing guidance still quotes the same figures: 5 km/h plus an extra minute for every 10 metres of ascent.

Worked example

A 12 km walk with 800 m of ascent:

• Distance: 12 km ÷ 5 km/h = 2.4 hours = 2h 24m
• Ascent: 800 m × 1 min per 10 m = 1h 20m
• Walking time: 3h 44m — before any stops

Naismith's rule assumes a reasonably fit walker, good conditions and no breaks, so it is best treated as a minimum. Another way to picture it is Scarf's equivalence: 1 metre of climbing costs about the same time as 7.92 metres of flat walking, so that 800 m climb is like adding 6.3 km to the route. The calculator shows this "equivalent flat distance" for your walk.

Langmuir's corrections for going downhill

Plain Naismith ignores descents entirely. Eric Langmuir's refinement, widely taught in UK mountain leadership, adjusts for them depending on how steep they are:

• Gentle descents (5–12°): subtract 10 minutes for every 300 m you descend — you can stride out.
• Steep descents (over 12°): add 10 minutes for every 300 m — you slow down to protect your knees and footing.
• Under 5°: no adjustment.

Choose Langmuir (by steepness) in the descent setting and the calculator works out the angle of every downhill section. With a GPX file it's measured directly; with manual entry it assumes each leg's descent is spread evenly. In practice Langmuir's gentle-descent bonus can be optimistic on rocky UK mountain paths, which is why the calculator defaults to classic Naismith.

Tobler's hiking function

Geographer Waldo Tobler published a formula in 1993 that gives walking speed as a smooth curve of slope: speed = 6 × e^{−3.5 × |slope + 0.05|} km/h. It predicts about 5 km/h on the flat, a top speed of 6 km/h on a slight 5% downhill, and a steady slowdown as paths get steeper in either direction. Because it treats every gradient individually, Tobler works best with a GPX file. The calculator scales the curve so that its flat speed matches yours.

Typical walking speeds: slow, average and fast

The presets use these figures. They're starting points — your own timings from previous walks are always better.

For comparison, the NHS describes a brisk walk as about 3 miles an hour — right in the "average" band. On the section-speeds setting, the presets use uphill speeds of 2.5, 3.5 and 4.5 km/h and downhill speeds of 3.5, 4.5 and 5.5 km/h along the path.

How to find your personal pace

1. Flat speed: time yourself over a known flat distance of at least 2–3 km at a pace you could hold all day. Divide the distance by the time in hours.
2. Climbing rate: on a hill walk you've done, take your total walking time, subtract the flat-speed time for the distance, and divide what's left by the ascent in hundreds of metres. That's your minutes per 100 m.
3. Descent: if you're noticeably slower going down, enter a positive figure under "My own figure" for descent time per 100 m.

Enter any of these and the preset switches to My own pace — the calculator remembers your settings on this device for next time. If you know your pace in minutes per km or mile, the pace converter turns it into km/h or mph.

Worked examples: Ben Nevis and Yr Wyddfa (Snowdon)

Real routes show why the walker type matters as much as the formula:

"Slow walker + breaks" uses 4 km/h plus 1 hour per 450 m, a 5-minute stop every hour and a 30-minute lunch. Notice that it lands inside the times usually quoted for these mountains, while bare Naismith is well under. If you're not a regular hillwalker, plan with the slow preset.

How much time to allow for breaks

Rules like Naismith's give moving time only. A realistic day includes stops for water, layers, map checks, photos and food. A common allowance is 5–10 minutes every hour plus 20–30 minutes for lunch. The calculator spreads your short breaks through the walk, puts the long stop at the halfway point, and includes them all in the finish time and the route card's arrival times. Larger groups and families with children typically stop more often — time a couple of your own walks to calibrate.

Using a GPX file

A GPX file is the standard format for sharing walking routes. You can export one from OS Maps, Komoot, Strava, AllTrails, Outdooractive, Garmin Connect and most GPS watches and apps. When you upload one, the calculator:

• reads the track (or route) points and their elevations — in your browser; the file never leaves your device;
• resamples the route every 20 m and smooths elevation noise, so random GPS jitter isn't counted as climbing;
• classifies every stretch as uphill, flat or downhill and applies your chosen pace to each one;
• draws a colour-coded elevation profile and builds a route card with one leg per km (or mile).

Use Walk it in reverse to see how the time changes if you do a route the other way round — often a big difference when one side is steep. If a GPX file has no elevation data, the route is timed as flat and you can copy its distance into manual entry and add the ascent yourself.

Why does my ascent differ from other apps?

Total ascent is surprisingly hard to measure. Summing every tiny up-and-down between GPS points can overstate the climb several times over on a noisy recording, while heavy smoothing understates it on short, steep bumps. Different apps choose different settings, so it's normal for them to disagree by 10–20%. The calculator shows both its smoothed figure and the raw total so you can judge.

Terrain, weather and daylight

Rough, pathless or boggy ground can slow you by 20% or more — Aitken's variation of Naismith's rule drops from 3 mph on paths to 2.5 mph on other terrain — and scrambling, snow or deep heather slows you further. Strong wind, rain and poor visibility all add time too, so be generous in winter.

Daylight is the limit that catches people out. In December, much of the UK gets less than eight hours of daylight, and northern Scotland less still. Enter your date, start time and walking area and the calculator shows the sunset time and warns you if your estimated finish is close to or after dark. On a long winter walk, set a turnaround time and stick to it.

Staying safe on the hills

Any walking time estimate is a planning aid, not a promise. Before a hill walk, check the mountain weather forecast, carry a map and compass (and know how to use them), pack a head torch and warm layers, and tell someone your route and expected finish time — the printable route card above is ideal for this. AdventureSmart UK has a quick checklist. In an emergency in the UK hills, call 999 or 112 and ask for the Police, then Mountain Rescue.