UNDERSTAND THE METHOD
How to use this calculator
Enter weight and exercise duration. Choose an exercise rate or use your own measured sweat rate. This planning estimate starts at 30 mL per kilogram and adds the selected adjustments.
What the result can tell you
This combined formula is a planning heuristic, not a validated individual prescription. Total water includes food and all beverages. It does not apply to a prescribed fluid restriction. Drinking beyond need can also cause harm.
Common questions
What is included in the daily water estimate?
The estimate starts at 30 mL per kg and adds the selected exercise, climate, pregnancy, breastfeeding, and category adjustments. Total water includes food and all beverages.
Can I use this with a prescribed fluid restriction?
No. This combined formula is a planning heuristic, not a prescription. It does not apply to a prescribed fluid restriction, and drinking beyond need can cause harm.
Sources & limitations
Sources checked September 12, 2026. These notes identify methods and assumptions. They have not received an independent clinical review.
- Water intake reference values and variation in requirements.doi.org
- Exercise fluid replacement and individual sweat rates.pubmed.ncbi.nlm.nih.gov