How much water for a hike? The math and 6 bottles rankedNo. 1 holds 1.5L at 36g

How much water to carry comes from the formula on the Central Council for Mountain Accident Prevention's Safety Card: body weight (kg) × hours (h) × 5. For 60kg and 5 hours, that's 1,500ml. No. 1 holds that 1,500ml in one bottle at just 36g: the EVERNEW Water Carry 1500ml.

How many liters of water for a hike? 60kg for 5 hours is 1.5L

The Central Council for Mountain Accident Prevention's Safety Card gives a formula for the amount of water. Water (ml) = body weight (kg) × hours (h) × 5. For a 60kg person walking 5 hours, that's 60 × 5 × 5 = 1,500ml.

The same card also recommends drinking 500ml before you set out, and finding out where there are huts or water points where you can get water. Bottle capacity is worked backward from this number.

How I chose

The first thing I looked at was how many bottles the formula's amount takes to carry. Next I calculated how many grams of container it takes to carry 1L of water, and that's where I split the upper and lower ranks.

Hiking in Japan and abroad, I've found that stretches without water points can be longer than you expect. So I picked the light container first, then added a heavy insulated bottle only for hot drinks, and ordered them that way. This ranking is made from what you can buy on Rakuten.

Three ways to choose a hiking bottle

• Amount: body weight × hours × 5, minus what you can refill at water points
• Container weight: soft bottles are about 21–32g per liter, insulated bottles about 433–560g
• Temperature: if you carry a hot drink in winter, read the heat retention figure

Quick table of the 6 hiking bottles

Scroll the table sideways →

How is a mountain bottle's "80°C or above" measured?

Thermos's heat retention is the temperature of the water after 6 hours, with 95°C boiling water filled to just under the inner stopper at a room temperature of 20°C. The 0.9L FFX-902 holds 80°C or above, and the 0.5L FFX-502 holds 77°C or above.

The 0.75L FFX-752 holds 78°C or above, so across the three, the bigger the bottle, the higher the number. If you want warmth to last, choose the bigger one.

How many grams of container to carry 1L?

Container weight per liter is about 21g for the Water Carry 2000ml against about 560g for the FFX-502. Even for the same 1L of water, the container alone makes a difference of 500g or more.

So I put most of the formula's amount in soft bottles, and use the mountain bottle only for the hot drink I carry in winter. This way you can carry 1.5L of water and 0.9L of hot water in 36g + about 390g.

Why this order

No. 1 EVERNEW Water Carry 1500ml | 1.5L at 36g

The 1,500ml for 60kg over 5 hours fits in exactly one bottle. The container is 36g. It's the same 1.5L as a plastic bottle, so it's easy to judge the amount. The combination of this volume and this lightness, which lets you gather day-hike water into one bottle, is what decides it.

Its heat tolerance goes up to 90°C, and it doesn't insulate. It suits people who want to carry their drinking water together, summer and winter.

No. 2 Thermos Mountain Bottle FFX-902 | 80°C or above after 6 hours

Filled with 95°C water at a room temperature of 20°C, it holds 80°C or above after 6 hours, the highest number of the three mountain bottles. With 0.9L, you can add hot water to instant noodles or freeze-dried meals up on the mountain.

It weighs about 0.39kg, more than 10 times No. 1. Here's the weak spot. It suits people who want to carry a hot drink in winter.

No. 3 EVERNEW Water Carry 900ml | the lightest of the six at 29g

A 900ml size that works well in place of a bottle. 29g is the lightest figure of the six. It's a three-layer build of nylon and low-odor polyethylene.

To carry the formula's 1,500ml you need two, which come to 58g together. It suits short mountains, and people who can refill at water points.

No. 4 EVERNEW Water Carry 2000ml | about 21g per liter

Container weight per liter is about 21g, the smallest of the six. It's a size for use at a campsite, where you can set out water to last until morning.

If you don't use up 2L on a day hike, the empty part is just weight you carry. It suits people on tent-camping trips who carry water from a water point.

No. 5 Thermos Mountain Bottle FFX-752 | 0.75L, 78°C or above

78°C or above after 6 hours, 2°C behind the FFX-902. It weighs about 0.36kg, about 0.03kg lighter than the 0.9L model.

But per liter it's about 480g, which works out heavier than the 0.9L model. It suits people who want to keep the height down inside the pack.

No. 6 Thermos Mountain Bottle FFX-502 | a 0.28kg mountain bottle

At 0.28kg it's the lightest of the mountain bottles, and it's 23.5cm tall. After 6 hours it holds 77°C or above, enough to carry a cup's worth of hot water.

At about 560g per liter it's the heaviest of the six, heavy for its volume. It suits people who want to carry just 1–2 cups of tea or soup.

Who is each for? Soft bottles and mountain bottles

A soft bottle fits a day hike without water points, where you carry the formula's amount as is. Once it's empty you can roll it up, so the pack is lighter on the way down. Its heat tolerance is up to 90°C, so I recommend using freshly boiled water straight from the pot.

A mountain bottle fits when you want a hot drink at a winter break, and when you want to make instant noodles on the mountain without boiling water. Leave summer water to the light soft bottle, and the pack stays light. I compared stoves in hiking stove rankings.

If your current bottle carries the formula's amount, it's enough as is. On a short mountain with water points nearby, a 500ml plastic bottle is another way to choose.

What you use the mountain bottle's hot water for changes how much hot water you need. I worked out the amounts in the tent-camping meals and freeze-dried food article.

FAQ

How many liters of water should I carry on a day hike?

Use the Central Council for Mountain Accident Prevention formula: body weight × hours × 5. For 60kg and 5 hours, that's 1,500ml.

What bottle size is easiest to use on a hike?

A capacity that carries the formula's amount in 1 or 2 bottles. With these 6, split it up: a 1,500ml soft bottle for day-hike water, and a 0.5–0.9L mountain bottle for hot drinks.

Is water alone enough to drink?

The Safety Card says that sweat is water and salt, and recommends oral rehydration solution and sports drinks that contain salt. I worked out a rule of thumb for trail-food calories in the hiking trail food article.

Gear in this article

Ad · Images: Rakuten Ichiba

EVERNEW Water Carry 1500mlThermos Mountain Bottle FFX-902EVERNEW Water Carry 900mlEVERNEW Water Carry 2000mlThermos Mountain Bottle FFX-752Thermos Mountain Bottle FFX-502

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