Water Intake Calculator
Enter your weight, activity level and climate to estimate how much water you should drink each day for good hydration.
Not medical advice This is general hydration guidance, not medical advice. Individual needs vary with health conditions, medications, pregnancy and breastfeeding. Consult a healthcare professional for personalized advice.
Water Intake Calculator
Estimate your daily water goal
Baseline = weight (lb) × 0.5 to 0.67 oz per lb. Add ~12 oz per 30 minutes of exercise and more in hot/humid climates. Results are general guidance.
⚠️ Double-check important results. This is an educational estimate, not professional advice — and where it uses a rate, bracket or fee, those change over time. Verify anything you'll rely on, especially in legal, financial, tax or medical matters, and read our full disclaimer. Think a result is wrong? Tell us so we can fix it.
How Daily Water Intake Is Estimated
A common rule of thumb is to drink between half and two-thirds of your body weight in pounds, in ounces of water per day:
Baseline ounces = weight (lb) × 0.5 to 0.67
Adjustments: - Add ~12 oz per 30 minutes of exercise - Hot climate: add ~15–25% - Hot & humid: add ~25–40%
Pregnancy, breastfeeding, illness, altitude and certain medications change needs. Results are general guidance only.
- Baseline: 0.5–0.67 oz per lb of body weight
- Add for exercise, heat and humidity
- General guidance — not medical advice
Worked Example
Example: 160 lb, moderately active, hot climate.
- Baseline: 160 × 0.67 ≈ 107 oz - Activity adjustment: +12 oz (moderate) - Climate adjustment (hot): +20% ≈ +25 oz - Estimated daily goal ≈ 144 oz ≈ 18 cups ≈ 4.3 litres
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Open calculator →Frequently Asked Questions
Does coffee count toward water intake?
Coffee and tea contribute to fluid intake, though caffeine has a mild diuretic effect. Water is still the best choice for hydration.
Can you drink too much water?
Yes — very large amounts in a short time can cause hyponatremia (dangerously low sodium). This is rare and mainly a risk during extreme endurance events.
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