💧 Free Online Tool

Daily Water Intake
Calculator

Find out exactly how much water you should drink based on your age, weight, height and activity level.

1 / 2  — Your Details
2 / 2  — Activity Level
2.5
Liters / Day
10
Cups (~250ml)
2500
Milliliters
5
Bottles (500ml)
Calculating...

💡 How to reach it

Drink one large glass (300ml) right after you wake up
Have a glass before every meal — it helps hydration and portion control
Take a small sip every time you pick up your phone
Drink 200ml every 20 minutes during exercise
Drink extra water after coffee — how much? →

Track this goal with Suu

Enter the goal you calculated into the Suu app — reach it with smart reminders, friend leagues and detailed stats.

Factors that affect your water needs

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Body Weight

Basic rule: 30–35 ml per kilogram. For 70 kg that's a base of about 2.1–2.45 L. People with high muscle mass need a little more.

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Activity Level

Intense exercise can cost 0.5–2 L of sweat per hour. Very active people need 50–70% more water per day than sedentary people.

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Climate & Heat

Hot, humid weather increases sweat loss. In summer your needs can be 0.5–1 L higher than in winter.

Coffee & Tea

Caffeinated drinks have a mild diuretic effect. If you drink 3+ cups of coffee a day, add 200–300 ml of extra water. Detailed calculation →

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Water from Food

About 20–30% of daily water comes from food. People who eat lots of fruit and vegetables need slightly less from drinks.

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Health Conditions

Pregnancy, breastfeeding, kidney stones or certain medications change your needs. Consult your doctor in these cases.

Water needs by body weight

Reference values for average, active adults.

Body WeightSedentaryModerately ActiveVery Active
50 kg1.5 – 1.8 L2.0 – 2.2 L2.5 – 2.8 L
60 kg1.8 – 2.1 L2.3 – 2.6 L2.8 – 3.2 L
70 kg2.1 – 2.5 L2.7 – 3.0 L3.2 – 3.7 L
80 kg2.4 – 2.8 L3.1 – 3.4 L3.7 – 4.2 L
90 kg2.7 – 3.2 L3.5 – 3.8 L4.1 – 4.7 L
100 kg3.0 – 3.5 L3.8 – 4.2 L4.5 – 5.0 L

* Values are a general reference. Your doctor's advice always takes priority.

Frequently Asked Questions

Is 2 liters of water a day enough?
For a sedentary, average-weight adult, 2 liters may be enough. But if you exercise, are heavier or live in a hot climate, you need more. The calculator above gives a value tailored to you.
Can drinking too much water be harmful?
Rarely, excessive water intake risks "hyponatremia" (low blood sodium). This usually appears only when more than 3–4 liters are consumed in a short time. For someone with healthy kidneys under normal conditions the risk is minimal. A maximum of 0.8–1 L per hour is recommended.
Is drinking water on an empty stomach in the morning good?
Yes — drinking 1–2 glasses right after waking jump-starts your metabolism, closes the overnight fluid gap and prepares your digestive system. Many health experts recommend it. The Suu app lets you set a morning reminder.
What are the signs of dehydration?
Early signs: mild headache, trouble concentrating, dry mouth, dark yellow urine. Moderate: dizziness, fatigue, palpitations. If you feel thirsty you're already a little behind — Suu reminds you when you fall behind your goal.
Do coffee and tea count toward water?
Partly. Tea and coffee contain fluid and contribute to your needs, but because of caffeine's mild diuretic effect they don't count as 100% water. Filter coffee contributes about 60% hydration, tea about 70%. Coffee dehydration calculator →

This tool provides general guidance and is not medical advice. Consult a healthcare professional for your individual needs.

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