Why Hydration Matters
Water is essential for nearly every bodily function — from regulating temperature and transporting nutrients to cushioning joints and flushing waste. Even mild dehydration (1–2 % body weight loss) can impair concentration, mood, and physical performance. The commonly cited "8 glasses a day" rule is a rough guideline; your actual needs depend on body weight, activity level, climate, and individual health factors.
How This Calculator Works
The baseline recommendation is approximately 35 ml per kg of body weight. This is then adjusted upward for higher activity levels, hot climates, and pregnancy or breastfeeding. The hourly schedule divides your total intake across 16 waking hours so you can sip consistently rather than gulping large amounts at once.
Signs of Dehydration
Common signs include dark-coloured urine, dry mouth, headaches, fatigue, and dizziness. If you exercise intensely or spend time in heat, increase your intake beyond the calculated amount and consider electrolyte supplementation for sessions lasting over an hour.
Disclaimer: This tool is for informational purposes only and does not constitute medical advice. People with kidney conditions, heart failure, or other medical conditions should consult a healthcare professional for personalised hydration guidance.