Your daily goal

2 500ml

2.5 litres of drinks a day

Rounded to the nearest 50 ml and kept between 1,500 and 5,000 ml. The goal is for what you drink; food adds water on top.

What your drinks really count

Add what you drank today. Each drink counts by how much it hydrates, and past 20 g of alcohol a day, alcoholic drinks take water away.

Drunk0ml

Net hydration0ml

Alcohol0g

Add a drink to see how much of it counts.

How the goal is calculated

The goal starts from your body weight, 33 ml per kilogram, which fits a typical, lightly active adult. It then adds or takes away water for the things that change how much you need:

Parts of the daily goal
Part	Choice	ml
Weight	per kg	33
Sex	Female	+0
	Not set	+200
	Male	+400
Activity	Sitting	−250
	Slightly active	+0
	Active	+500
	Very active	+1,000
Climate	Cool	−200
	Temperate	+0
	Hot	+500
Female only	Pregnant	+300
Female only	Breastfeeding	+700

The total is rounded to the nearest 50 ml and kept between 1,500 and 5,000 ml. A 70 kg adult with sex not set, slightly active, in a temperate climate gets 2,310 + 200 = 2,510, so 2,500 ml.

The result falls between the European (EFSA) and US (National Academies) recommendations for drinks. Men need a little more at the same weight, and very active people about a litre more than people who sit most of the day.

How much each drink counts

Not every drink hydrates like water. What counts is the amount multiplied by a hydration factor:

Hydration factor for each drink
Drink	Factor
Water, coffee, tea, fresh juice, soda, sports drink	×1
Milk	×1.2
Electrolytes	×1.5
Beer (5%)	×0.6
Wine (12%)	×0
Spirits (40%)	×−2.2

Coffee, tea, juice and soft drinks hydrate about as well as water. Milk and rehydration drinks are kept by the body a little better than water. Alcohol makes you lose about 10 ml of extra urine per gram, so beer counts only in part, wine adds nothing and spirits take water away.

Up to 20 g of alcohol a day (about one 500 ml beer), alcoholic drinks count with these factors. Past that, the water in them no longer counts, only the alcohol: beer ×−0.4, wine ×−1, spirits ×−3.2. A first 500 ml beer adds about 300 ml; a second one takes about 200 ml away.

Questions

How much water should I drink a day?

For most adults, somewhere between 1.5 and 3.5 litres of drinks a day. It depends on your weight, sex, how active you are and how warm it is where you live: use the calculator above for your own number. The goal is for drinks; food adds some water on top.

Does coffee count towards my water intake?

Yes. Studies found no dehydration with moderate daily coffee intake, so coffee and tea count like water. More in does coffee dehydrate you?

Does alcohol dehydrate you?

Yes. Alcohol makes your body lose about 10 ml of extra water for every gram of alcohol. A beer still gives you some water back; wine about breaks even; spirits take more water than they give.

How much water should I drink after a beer?

The first 500 ml beer of the day still hydrates you a little. Each one after it takes about 200 ml of water away, so drink about a glass of water per extra beer. Add your drinks above to see the exact number, or read how much water to drink after alcohol.

Does the calculator replace medical advice?

No. These are general estimates for healthy adults. If you have a medical condition, follow your doctor’s guidance on fluids.

Sources

Track it every day with Hydra

iPhone and Apple Watch

Hydra uses this same formula for your daily goal, counts every drink by its factor, and tells you how much water offsets the alcohol, right when you log it.

Water intake calculator