Water Intake Calculator

Calculate your recommended daily water intake based on weight and activity level

Your Details

Enter your details and click Calculate

Daily Water Recommendation

— litres / day

—

ml per day

—

Glasses (250 ml each)

Breakdown
Base intake (weight × 35 ml) —
Activity bonus —
Climate bonus —

These are general guidelines. Individual needs vary based on health conditions, diet, and other factors.

How to Use

  1. Enter your Body Weight (in kg).
  2. Select your Activity Level (Sedentary, Moderate, Active).
  3. Select your Climate (Temperate, Hot & Humid, or Very Hot) — this adjusts for sweating.
  4. Click Calculate to see your recommended daily water intake in litres and number of glasses (250 ml each).
  5. 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

PersonRecommended Daily Intake
Sedentary adult (temperate)~2.0 – 2.5 litres
Active adult (moderate exercise)~2.5 – 3.5 litres
Hot climate / outdoor worker3.5 – 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.

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