The amount of water you should drink per day depends on several factors, including your activity level, sex, and body size. The U.S. National Academies of Sciences, Engineering, and Medicine recommends about 15.5 cups (3.7 liters) of fluids a day for men and about 11.5 cups (2.7 liters) of fluids for women, including fluids from water, other beverages, and food.However, this is a general guideline, and individual needs may vary. Here are some tips on how to determine how much water you should drink based on your activity level:

1. Use a water intake calculator: You can use a water intake calculator to determine how much water you should drink based on your body weight and activity level

2. Consider your activity level: If you do any activity that makes you sweat, you need to drink extra water to cover the fluid loss. Drinking water before, during, and after a workout is essential. The more you exercise, the more water you drink to replace lost fluids.

3. Listen to your body: Pay attention to your body's thirst cues, and drink water when thirsty. If you're feeling thirsty, your body is already dehydrated.

4. Adjust your intake: You might need to modify your total fluid intake based on several factors, including exercise, environment, and health conditions. For example, you may need to drink more water in hot and humid temperatures to reduce your risk of overheating.

Remember that staying hydrated is essential for good overall health, and drinking enough water can help support physical performance, prevent headaches and constipation, and regulate internal body temperature. While the general guideline is about 15.5 cups (3.7 liters) of fluids a day for men and about 11.5 cups (2.7 liters) of fluids for women, individual needs may vary based on several factors.