How to Use This Calculator
Enter your bodyweight and daily exercise minutes, pick your climate, and your personalized daily water target updates instantly across liters, ml, cups, and fluid ounces. For the full explanation of where this formula comes from and how hydration actually works, see the "How to Use the Water Intake Calculator" section of our complete guide.
Read the full guide first for the best context: why the old "8 glasses a day" rule is a myth, how sweat rate and climate actually affect fluid needs, the risks of both under- and over-hydration, and a detailed worked example for every calculation on this page are all covered in our Daily Water Intake Calculator Guide 2026 →
This calculator provides general estimates for informational and educational purposes only. It is not medical advice. Individual fluid needs vary based on health conditions, medications, and other factors. Always consult a doctor before making significant changes to your fluid intake, particularly if you have a kidney, heart, or liver condition.