Overview
Hydration affects performance, focus and recovery. This calculator estimates a daily water target from your bodyweight plus a bonus for how active you are.
How it's calculated
Enter your weight and activity level. The base is ~35 ml per kg of bodyweight, plus 0–1000 ml depending on activity. The result is shown in litres, millilitres and roughly-240 ml cups.
ml = bodyweight(kg) × 35 + activity bonus
How to read your result
This is a baseline, not a hard rule — heat, sweat rate and diet all shift your needs. A simple field check: pale-straw urine usually means you're well hydrated.
Frequently asked questions
Does coffee or tea count?
Yes — fluids from drinks and water-rich foods all contribute. The target is total daily fluid, not plain water only.
Can you drink too much water?
Rarely, but chugging far beyond your needs in a short time can dilute sodium. Spread intake across the day.
Should I drink more on training days?
Yes — that's what the activity bonus accounts for. Add extra to replace heavy sweat losses in hot sessions.
Sources & references
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific opinion on dietary reference values for water. EFSA Journal. 2010;8(3):1459.
- Institute of Medicine. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. National Academies Press; 2004.
Medical disclaimer
This calculator is for general educational purposes only and is not medical advice. Estimates are based on population formulas and may not fit your individual situation. Consult a qualified healthcare or fitness professional before making health, nutrition or training decisions.