water intake

How much water should I drink a day?

A personalized daily water intake target in ounces and liters, based on your body weight, activity level, and climate.

daily water target
100 oz2.97 L
roughly 12.5 cups or 11.9 glasses
suggested reminders
7:0013 oz (371 ml)
9:0013 oz (371 ml)
11:0013 oz (371 ml)
13:0013 oz (371 ml)
15:0013 oz (371 ml)
17:0013 oz (371 ml)
19:0013 oz (371 ml)
21:0013 oz (371 ml)

How this calculator works

The baseline is around 35 ml per kilogram of body weight (roughly 0.5 oz per pound), a common rule of thumb used to estimate daily water needs. The tool converts that into ounces, liters, and rough cup counts, then adjusts the total for two everyday factors: activity level and climate.

Light activity adds about 10 %, moderate 20 %, and intense 35 %. A hot climate adds another 15 %. The suggested-reminder schedule spreads the total across eight two-hour windows between 7 AM and 9 PM so you don't have to drink it all at once.

What can change your daily needs

Body weight is the strongest baseline driver, but plenty of things move it: exercise, heat and humidity, altitude, pregnancy or breastfeeding, illness, and certain medications. Most non-alcoholic drinks — including coffee and tea — count toward hydration, and water-rich foods like fruit, soup, and yogurt contribute too. If you have a medical condition that changes your fluid needs, follow your clinician's guidance instead of a generic calculator.

Related: pair with the calorie calculator for daily targets, or the BMI calculator for a body-composition reference.

Frequently asked

How much water should I drink a day?
A common baseline is around 35 ml per kilogram of body weight, which works out to roughly 0.5 oz per pound. For a 170 lb person that is about 91 oz (2.7 L) before adjusting for activity or hot weather. The calculator uses that baseline and adds a bump for activity level and climate so the target reflects your own situation.
How much water should I drink if I weigh 160 lb?
A 160 lb person weighs about 72.6 kg, so the baseline target is roughly 2.5 L or 86 oz a day. Enter 160 in the calculator and it will show the exact number in ounces, liters, and rough cup equivalents, then let you add adjustments for activity and climate.
Do coffee, tea, and food count toward hydration?
Yes. Most non-alcoholic drinks, including coffee and tea, count toward daily hydration, and water-rich foods like fruit, soup, and yogurt contribute too. The target here is total water from all sources, not glasses of plain water only.
Does the target change with exercise or hot weather?
Yes. Light activity adds about 10 %, moderate about 20 %, and intense about 35 %. A hot climate adds another 15 %. Toggle activity and climate on the calculator and the target updates immediately. General guidance only, if you have a medical condition that changes fluid needs, follow your clinician.