Water Intake Calculator
Find out how much water you should drink each day based on your weight, activity level, and South African climate conditions.
How to Use the Water Intake Calculator
Enter your body weight, select your typical activity level, and choose the climate most relevant to your location or lifestyle. The calculator gives you a personalised daily water intake target, accounting for the extra hydration needs of South Africa's warmer regions.
The Extended Calculator below shows a hydration timeline and a hourly drinking schedule. The Professional Calculator adds activity-specific hydration (MET-based), electrolyte needs, and a dehydration risk score.
Drinking Schedule
Hydration Tips
- Start with 2 glasses upon waking
- Drink a glass before each meal
- Keep a water bottle at your desk
Formula
Base: Body weight (kg) × 30 ml
Light Activity: +350 ml | Moderate Activity: +600 ml | Very Active: +1,000 ml
Warm Climate: +300 ml | Hot & Humid: +600 ml
Total: Base + Activity Adjustment + Climate Adjustment
Example
Person: 75 kg, moderately active, lives in Durban (hot climate)
Base = 75 × 30 = 2,250 ml
Moderate activity = +600 ml | Hot climate = +600 ml
Total = 3,450 ml (3.5 litres) per day
Exercise Sessions
Electrolyte Needs (estimate)
| Electrolyte | Est. Daily Need | Food Sources |
|---|---|---|
| Sodium (Na⁺) | 1660 mg | Salt, olives, cheese |
| Potassium (K⁺) | 664 mg | Banana, potato, avocado |
| Magnesium (Mg²⁺) | 166 mg | Nuts, dark chocolate, leafy greens |
These are rough estimates based on sweat loss. For precise needs during endurance sport, consult a sports dietitian.
Dehydration Signs & Prevention
Early signs (1–2% dehydration): Thirst, darker urine, reduced concentration
Moderate (3–4%): Fatigue, headache, dizziness, reduced exercise performance
Severe (5%+): Rapid heartbeat, confusion — seek medical attention
Your current risk: Low (0/10)