Water Intake Calculator
Enter your weight and how much you exercise to get your daily water target — in liters, cups, and bottles.
How the math works
The baseline of roughly 33 ml per kg (about half an ounce per pound) lines up with the Institute of Medicine's total fluid recommendations — about 2.7 L/day for women and 3.7 L/day for men including food moisture. Each half hour of exercise adds sweat losses on the order of 350 ml. Hot weather adds more; there's no bonus for drinking far beyond this.
You don't need to drown yourself
About 20% of your fluid comes from food — fruit, soup, yogurt all count, as do coffee and tea. The best real-world check isn't a formula at all: urine should be pale straw-colored. Dark yellow means drink up; totally clear all day means you can ease off. Thirst is a reliable guide for most healthy adults doing ordinary activity.
FAQ
- Do I need electrolyte drinks?
- For ordinary workouts under an hour, water is fine. Sports drinks earn their keep in sustained heavy sweating (90+ minutes, heat) or illness with fluid loss.
- How much water for weight loss?
- Water before meals can modestly help with fullness — a useful habit, not magic. Total calories still decide weight change.
- What about when sick?
- Fever, vomiting or diarrhea raise needs considerably; oral rehydration solutions are the evidence-based choice for significant losses. Ask a pharmacist or doctor when in doubt.
This tool provides general information only and is not medical advice. Kidney or heart conditions may require fluid limits set by your doctor.