Many people wonder how much water they should drink every day, especially during hot weather or when exercising. While the common advice of “8 glasses a day” is often repeated, experts say there is no single amount that works for everyone. Your ideal water intake depends on your body size, activity level, climate, diet, and overall health.

For most adults in the U.S., a good general guideline is around 6–8 cups of fluids per day, but your needs may be higher if you spend time outdoors, work out, sweat a lot, or live in a hot and humid area. Remember that water is not the only source of hydration — coffee, tea, milk, and water-rich foods like watermelon, cucumbers, tomatoes, and strawberries also contribute to your daily fluid intake.

Exercise, illness, and extreme temperatures can increase how much water your body needs. During workouts, especially longer or intense sessions, you lose fluids through sweat and may need extra water or drinks with electrolytes to replace lost minerals. Pregnant and breastfeeding women also generally need more fluids to support their body’s increased demands.

Signs that you may need more water include thirst, dark yellow urine, dry mouth, headaches, tiredness, dizziness, and muscle fatigue. The easiest way to stay hydrated is to drink regularly throughout the day, carry a reusable bottle, and pay attention to your body’s signals. However, drinking excessive amounts of water too quickly can also be dangerous, so balance is key.