How to calculate how much water you should drink a day This water calculator can help you to calculate the amount of water you should drink as daily requirement and how much water you need.
Daily Water Intake Calculator
Use this hydration calculator to learn how much water you should drink daily based on your weight and exercise time.
Your weight: The first step to knowing how much water to drink every day is to know your weight. The amount of water a person should drink varies on their weight, which makes sense because the more someone weighs the more water they need to drink. A 180 pound man and 100 pound woman require different amounts of water every day.
Multiply by 2/3: Next you want to multiply your weight by 2/3 (or 67%) to determine how much water to drink daily. For example, if you weighed 175 pounds you would multiply that by 2/3 and learn you should be drinking about 117 ounces of water every day.
Exercise Time: You will want to adjust that number based on how often you exercise since you are expelling water when you sweat. You should add 12 ounces of water to your daily total for every 30 minutes that you workout. So if you workout for 40 minutes daily, you would add 16.9 ounces of water to your daily intake.