Water Intake Calculator
Calculate your recommended daily water intake based on weight and activity level
Your Details
Enter your details and click Calculate
How to Use
- Enter your Body Weight (in kg).
- Select your Activity Level (Sedentary, Moderate, Active).
- Select your Climate (Temperate, Hot & Humid, or Very Hot) — this adjusts for sweating.
- Click Calculate to see your recommended daily water intake in litres and number of glasses (250 ml each).
- The result also shows the recommended intake for morning, midday, and evening hydration spread.
Why Hydration Matters
Water makes up about 60% of the human body and is involved in virtually every physiological process — digestion, circulation, temperature regulation, joint lubrication, and waste elimination. Even mild dehydration (1–2% body water loss) can impair physical performance, concentration, and mood.
General Hydration Guidelines
| Person | Recommended Daily Intake |
|---|---|
| Sedentary adult (temperate) | ~2.0 – 2.5 litres |
| Active adult (moderate exercise) | ~2.5 – 3.5 litres |
| Hot climate / outdoor worker | 3.5 – 5.0 litres |
| Pregnant woman | +0.3 litres above baseline |
| Breastfeeding woman | +0.7 litres above baseline |
Practical Hydration Tips
- Start each morning with a full glass of water before tea or coffee.
- Keep a labelled 1-litre bottle on your desk — aim to finish it twice a day.
- Set phone reminders every 2 hours if you tend to forget.
- Eat water-rich foods: cucumber (96% water), watermelon (92%), tomatoes (95%).
- After every 30 minutes of exercise, drink at least 200–300 ml to replace sweat losses.
The Urine Colour Test
The simplest hydration check: your urine should be pale yellow (straw-coloured). Dark yellow or amber means drink more. Completely clear urine for extended periods may indicate over-hydration — both extremes are undesirable.
Frequently Asked Questions
The commonly cited recommendation is 8 glasses (2 litres) a day, but actual needs vary. A more personalised rule is 35 ml per kg of body weight. A 70 kg person needs about 2.45 litres. Exercise, heat, breastfeeding, and illness all increase requirements. Our calculator adjusts for weight, activity level, and climate.
Yes — all fluids count, including tea, coffee, milk, and juice. The old myth that coffee dehydrates you has been largely disproved; the net hydration effect of a cup of coffee is positive. However, sugary drinks and alcohol are not ideal hydration sources — plain water remains the best choice.
Mild: dark yellow urine, thirst, dry mouth, fatigue. Moderate: headache, reduced concentration, dizziness. Severe: rapid heartbeat, confusion, sunken eyes. A simple test: your urine should be pale yellow (like lemonade). Dark amber urine almost always means you need more water.
Yes — overhydration (hyponatraemia) can occur when you drink far more water than your kidneys can process (more than ~1 litre/hour for extended periods). It is rare in healthy adults but can be dangerous during endurance sports. For most people, thirst is a reliable guide — drink when thirsty, don't force excessive amounts.