Planning a Day Hike With All Six Calculators

Each calculator on this site answers one question. Used together, in the right order, they turn a route on a map into a plan you can check the night before: how hard the day is, how long it takes, when to turn back, how much water to carry, what the pack weighs and how much food you need. This guide walks one hypothetical day through all six. The route and the hiker are invented; swap in your own numbers.

The day

A 72 kg hiker is planning an out-and-back to a summit: 14 km in total with 850 m of climb, on a rocky trail. It is late summer, the forecast is dry with a high of 26°C (about 79°F), and sunset is at 18:10. They plan to start at 08:00.

1. How hard is it?

The Trail Difficulty Rating converts 14 km and 850 m into 8.7 miles and 2,789 feet and gives a Shenandoah rating of 220.3, in the very strenuous band, and 11.5 energy miles. The question to ask is whether that fits recent experience. If the hiker's longest recent day was around 120 to 150, this is a big step up; see stepping up to a strenuous hike. If they regularly do days above 200, it is a normal outing.

2. How long will it take?

The Hiking Time Calculator at average pace gives 4h 13m by Naismith's rule: 2.8 hours for the distance and 1.42 hours for the climb. The Tobler cross-check is 3h 26m. The route is steep enough for the two to differ by three quarters of an hour, so the plan uses the longer figure.

That is moving time. Adding 45 minutes for breaks (a snack every hour or so and a stop at the top) brings the plan to just under five hours on the trail, 4.97 hours as a decimal.

3. When must they turn back?

Into the Daylight Turnaround Calculator: start 08:00, sunset 18:10, 4.97 hours, the default 60-minute buffer and the default 25% slower return.

• Latest safe finish: 17:10.
• Turn back by: 12:04.
• Projected finish: 13:36.
• Margin: 214 minutes.

A comfortable plan. The outward leg should take about two and a half hours, putting the hiker on the summit around 10:30, well before the turnaround. If they are not on top by 12:04, they turn back anyway. If afternoon storms were forecast, they would also need an earlier off-the-summit time; see planning to be down before storms.

4. How much water?

The Water Needs Calculator takes the 4.97 hours, 26°C and moderate effort. The temperature factor is 1.3, so the rate is 0.65 litres per hour, and the total is 3.23 litres. No electrolyte flag (that needs 28°C or more, strenuous effort and three hours or longer), but salty snacks are still a good idea on a warm climb. The route has no reliable water, so all of it is carried from the start. It is a planning estimate: on an exposed, sunny ridge the hiker might drink more, so a little extra is sensible.

5. What does the pack weigh?

The Backpack Weight Calculator: a 3.4 kg base weight (day pack plus the ten essentials), 0.7 kg of food and 3.23 kg of water.

• Consumables: 3.93 kg.
• Total: 7.33 kg, which is 10.18% of body weight, well within the 20% guideline (a rough guide for adults, not a medical limit).
• Base weight class: ultralight.

More than half the pack is water and food, which is typical of a summer day hike. See what the ten essentials weigh for what is in the base weight.

6. How much food?

The Hiking Calorie Burn Calculator, run as two legs with the 7.33 kg pack on rocky trail (terrain factor 1.2):

• Up: 7 km at a 12.1% average grade (850 m over 7 km) at 3 km per hour: about 545 W for 2.33 hours, 1,094 kcal.
• Down: 7 km at 4 km per hour: the calculator's standing-metabolism floor of 108 W for 1.75 hours, 163 kcal, a known underestimate for a steep descent.

Roughly 1,260 kcal or more for the walking, on top of normal daily needs. After a good breakfast, the 0.7 kg of food in the pack, a lunch and snacks, covers it with some to spare. See turning calories into a food bag.

How the numbers connect

The order matters because each answer feeds the next. Distance and climb give the rating and the time. The time, with breaks, gives the turnaround and the water. The water gives the pack weight. The pack weight goes into the calorie estimate. Change one input and several outputs move: a hotter day means more water, which means a heavier pack, which means more energy and a slower pace, which means a later finish. Running the whole chain again takes a couple of minutes, and it is worth doing whenever the plan changes.

When the day changes

Two common changes show how the chain responds.

A hotter forecast. If the forecast rises to 32°C (about 90°F), the water calculator moves into the 28 to 33°C band with a factor of 1.6: 0.8 litres per hour and 3.98 litres in total, three quarters of a litre more. The pack goes to 8.08 kg, 11.22% of body weight. Still well within the guideline, but a hotter, heavier day is a slower one, and on an exposed climb heat is the bigger risk than weight. A sensible response is to start earlier, carry the extra water, rest in shade, and know the signs of heat exhaustion.

A late start. If traffic means starting at 10:00 instead of 08:00, the turnaround moves to 13:11, the projected finish to 15:36, and the margin falls from 214 minutes to 94. Still positive, but less than half the slack. A late start combined with a slow climb or a long lunch can use it up, so this is the day to keep breaks short and respect the turnaround strictly.

What none of the calculators checks

Every figure here is an estimate for a fit adult on a reasonable trail in decent conditions. Before the hike, the hiker still needs to:

• Check the land manager's current conditions, closures, permits and rules for the area.
• Check the mountain forecast, including wind, storms and temperature at the summit, not just the trailhead.
• Read the route description for footing, exposure, scrambling and water crossings.
• Pack the ten essentials: navigation, headlamp, sun protection, first aid, knife or repair kit, fire where permitted, emergency shelter, extra food, extra water with a way to treat more, and extra clothing.
• Charge the phone, and download the map for offline use.
• Tell someone the route, the start time and when to expect them back, and know the local emergency number.

And on the day, two rules override every number: turn back at the turnaround time, and turn back earlier if the weather turns or anyone shows signs of heat illness, cold or injury.