Water Intake Calculator
Estimates daily fluid needs from body weight and exercise.
Your result
Estimate only. Results update as you type.
How this calculator works
Fluid = 35 ml per kg of body weight + about 12 ml per minute of exercise.
Worth knowing
Australian summers raise fluid needs. Drink more in hot weather even if you don’t feel thirsty.
Guides for this calculator
- Water Intake Calculator: Formula, Example and What the Result Means
- Water Intake: What to Check Before You Trust the Number
Questions
- Are these calculators medical advice?
- No. They provide general information. See your GP or visit healthdirect.gov.au for personal advice.
- Do they work for children?
- No. Adult formulas are used throughout. Children’s growth is assessed differently.
- Where do the formulas come from?
- Each calculator page names the formula used, such as Mifflin-St Jeor for BMR or the US Navy method for body fat.
This calculator gives general estimates using published Australian rates and formulas. It doesn’t consider your personal circumstances. Check current figures with the ATO, your state government or a qualified professional before making decisions. See our disclaimer.