How Much Water Should You Drink Per Day?

Quick Answer

Quick Answer: A common guideline is 33 ml per kg of body weight per day. A 70 kg (154 lb) person should drink about 2.3 liters (77 oz) daily. Use our Water Intake Calculator.

The 8-glasses rule

"8 glasses a day" (~2 liters) is a rough average, not personalized. Weight-based formulas are more tailored.

Imperial rule of thumb

Some guidelines suggest half your body weight in ounces of water per day (e.g., 160 lb → 80 oz).

Factors that increase needs

Exercise, hot weather, pregnancy, and illness increase fluid requirements.

Try It Yourself

Calculate your daily target with the Water Intake Calculator.

Disclaimer: Not medical advice.