How much water should I drink a day? A simple guide

You have probably heard "8 glasses a day". It is easy to remember, but the real answer depends on you. Your size, how much you move, the weather and even what you eat all change how much water your body needs.

This guide gives you real numbers, a simple way to find your own goal, and tips that make it easy to reach.

The short answer

Health experts give these general amounts of total water per day. "Total" means from all drinks and from food. Food usually gives about 20 percent of it.

Take away the water you get from food, and most adults need roughly 2 to 3 liters from drinks. That is about 8 to 12 glasses of 250 ml.

Why your number is different

• Body size. A bigger body needs more water. A common starting point is about 30 to 35 ml for every kilogram you weigh.
• Activity. Exercise and physical work make you sweat. Add water for every active hour.
• Weather. Hot or humid days, and places like much of India in summer, can easily add half a liter or more.
• Health and life stage. Pregnancy, breastfeeding, fever and some medicines change your needs. Some heart and kidney conditions need less water, so always follow your doctor's advice.

A simple way to find your goal

Here is the same formula Sipsway uses to suggest a starting goal:

1. Multiply your weight in kg by 33. For 68 kg, that is about 2,250 ml.
2. Add 350 ml if you are lightly active, or 700 ml if you exercise hard most days.

On hot days, drink a little more than your goal.

Try it with our water intake calculator. It does the maths for you.

Easy ways to reach your goal

• Drink a glass when you wake up, before your morning tea or coffee.
• Keep a bottle where you can see it, on your desk or in your bag.
• Link water to things you already do: with every meal, after every meeting.
• Use gentle reminders that stop once you are done.
• Track it. Seeing your progress is surprisingly motivating.

Can you drink too much water?

Yes, but it is rare for healthy people. Drinking a very large amount in a short time can lower the salt in your blood. Spread your water across the day and listen to your thirst. You do not need to force huge amounts.

The bottom line

Most adults need about 2 to 3 liters from drinks each day, more when it is hot or you are active. Start with a goal based on your weight, adjust it to how you feel, and make it easy with small habits.

Sources: Mayo Clinic, EFSA. This article is general information, not medical advice.