How much water should I drink a day?
A simple estimate to start with — and the everyday signals that matter more than any number.
Hydration doesn't have to be complicated. A rough daily target gives you a starting point, and then your own body — thirst and urine color — tells you whether to drink a little more or less.
The short answer: a good starting estimate is about half your body weight (in pounds) in ounces of water per day, adjusted up for heat, exercise, and pregnancy/breastfeeding. Then let thirst and pale-yellow urine be your everyday guide.
Estimate your daily water
Hydration Target
A simple daily water goal based on your body and activity.
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A few things worth knowing
- Other fluids count. Coffee, tea, milk, and water-rich foods all contribute.
- Move the number up on hot days, during and after exercise, and when you're pregnant or nursing.
- Watch the color. Pale straw = well hydrated; dark yellow = drink more.
- Spread it out. Sipping through the day beats chugging all at once.
Common questions
How much water should I drink a day?
A common starting estimate is roughly half your body weight in pounds, in ounces of water, per day — so about 75 ounces for a 150-pound person. Adjust upward in hot weather, when you exercise, and during pregnancy or breastfeeding. Day to day, your thirst and the color of your urine are better guides than any fixed number.
Is the “8 glasses a day” rule actually true?
It is a reasonable rule of thumb, not a scientific law. Needs vary a lot with body size, activity, climate, and health. Eight cups is a fine default for many people, but some need more and some less — let thirst and urine color fine-tune it.
Do coffee, tea, and food count toward hydration?
Yes. Most fluids count, including coffee and tea, and water-rich foods like fruit, vegetables, soup, and yogurt contribute too. The mild diuretic effect of normal coffee or tea intake does not cancel out the fluid you get from them.
What are signs I’m not drinking enough?
Dark yellow urine, thirst, dry mouth, headache, fatigue, and feeling lightheaded can all signal you need more fluids. Pale, straw-colored urine usually means you are well hydrated.
This is general education, not medical advice. Some health conditions require specific fluid targets — check with your healthcare provider if that applies to you.