How do I use the Hydration Calculator?
Enter your values in the fields and the result updates instantly as you type.
Hydration Calculator
Calculate daily water intake recommendation based on weight and activity level. Enter your values, review the formula, and use the worked result as a quick check for everyday planning.
Hydration Calculator
Calculate daily water intake recommendation based on weight and activity level.
Your body weight in kg
sedentary, light, moderate, active, very_active
Minutes of exercise per day
Results
Base Requirement
2.31 L
Activity Adjustment
0.462 L
Exercise Additional
0.5 L
Total Daily Intake
3.272 L
Glasses (250ml)
13 glasses
Formula: Water (L) = Weight (kg) × 0.033 + Activity Adjustment
Disclaimer: This calculator provides a general estimate. Individual hydration needs vary based on climate, health conditions, medications, and activity intensity. Consult a healthcare provider for personalized recommendations.
Hydration Calculator: Daily Water Intake
Estimate how much water you should drink daily based on your body weight and activity level. Proper hydration supports energy, focus, digestion, and physical performance.
Formula
Base Intake = Weight (kg) × 0.033 liters. For active individuals, add 0.5–1.0 L per hour of exercise. The calculator adjusts recommendations based on the activity level you select.
Worked example
A 70 kg person with moderate activity: base = 2.31 L, plus 0.5 L for 30 min exercise = 2.81 L total daily intake.
Practical guidance
Signs of dehydration
Dark urine, dry mouth, headaches, fatigue, and dizziness are common signs. Thirst is a lagging indicator — drink before you feel thirsty, especially in hot weather or during exercise.
Sources beyond water
Tea, coffee, milk, fruits, and vegetables all contribute to hydration. Caffeinated drinks have a mild diuretic effect but still count toward your total. Alcohol does not — it dehydrates.
Frequently asked questions
What formula does this calculator use?
Water (L) = Weight (kg) × 0.033 + Activity Adjustment
Can I use decimal values?
Yes. Decimal inputs are supported for most calculators. Integer-based tools use rounded integer values where appropriate.
Is this calculator free?
Yes. CalcuNimble calculators are free and optimized for fast everyday use.