Staying hydrated is one of the simplest things you can do for your skin, energy and overall health — but how much water should you actually drink each day? The old “8 glasses a day” rule is just a rough guide. Your real needs depend on your body weight, how active you are and the climate you live in. Use the free water intake calculator below to get a personalised daily target in seconds.
Water Intake Calculator
Find out how much water you should drink each day.
Estimate only. Needs vary with health, pregnancy and medication. Ask a doctor if unsure.
How much water should you drink a day?
A common guideline is to drink around 30 to 35 ml of water per kilogram of body weight. For a 70 kg (154 lb) adult, that works out to roughly 2.1 to 2.5 litres a day. On top of that baseline, you need extra water when you exercise (you lose fluid through sweat) and when the weather is hot or humid. The calculator above adds all three factors together so you get a number that fits your life, not a one-size-fits-all figure.
Why staying hydrated matters for skin and health
Water helps your body regulate temperature, carry nutrients, cushion joints and flush out waste. For your skin specifically, good hydration supports a plumper, more radiant look and helps maintain the skin barrier. Even mild dehydration can leave you tired, headachy and less focused. Spreading your intake across the day — rather than gulping it all at once — keeps you hydrated more effectively.
Easy ways to drink more water
Start your morning with a glass of water before coffee, keep a reusable bottle within reach, and flavour plain water with lemon, cucumber or mint if you find it boring. Foods with high water content — cucumber, watermelon, oranges and soups — also count towards your daily total. If you often forget, set a reminder every couple of hours or use a marked bottle to track your progress.
Frequently asked questions
Does tea, coffee or juice count towards my water intake?
Yes. Most fluids, including tea, coffee, milk and juice, contribute to your daily hydration. Water is still the healthiest choice because it has no sugar or calories, but caffeinated drinks in normal amounts do count.
Can I drink too much water?
It is possible but rare. Drinking very large amounts in a short time can dilute the sodium in your blood, a condition called hyponatraemia. For most healthy people, drinking to thirst plus the target above is perfectly safe.
Should pregnant or breastfeeding women drink more?
Yes, fluid needs rise during pregnancy and breastfeeding. This calculator gives a general estimate only — if you are pregnant, breastfeeding or have a medical condition, follow your doctor’s advice.