If you're reading this in hopes of finding the perfect answer as to recommended water per day, here's a spoiler: It depends!

Unless you've been living in a cave your entire life, you've probably come across hundreds of articles promising you the final answer to this Very Important Question. But the truth is much more complicated than the simplistic "8 glasses a day" advice, despite how often this number gets repeated on social media. Here are some things to keep in mind.

There's no one-size-fits-all solution for water consumption

First off, every human body has a different base percentage of water, depending on factors such as age and sex. ThoughtCo. has a great primer on our different water levels, pointing out that the natural occurrence of water in the body could be as little as 45% to as much as 75%.¹

And that's just the baseline. Add in variables like exercise, diet, genetics, and climate, and what's normal for one person just isn't normal for another person of the same age and sex.

You are a different person every day

So we've established that all humans are unique, but here's one more thing to boggle your mind: You are not the same person you were yesterday, nor are you the same person you'll be tomorrow. Consider this scenario:

• YESTERDAY: It was terribly hot and humid all day, and you wanted to eat nothing but chilled fruits and salads with bottle after bottle of ice-cold water. You were sweating a lot because of the heat, but you also took in more water-rich foods and drank more water to keep cool.
• TODAY: It's workout day! You did an hour of cardio this morning, working up a great sweat. In the afternoon, you needed a boost at work, so you downed two lattes at your desk, but then skipped dinner.
• TOMORROW: It's a friend's birthday, and the forecast is calling for rain, so the plan is a cozy night in with your friend group. You're already expecting to eat nothing but sugary and salty junk foods, and maybe consume some alcohol before getting to bed much later than usual.

On all of these days, your needs will be different based on both how much you're moving, sweating, and sleeping, and what you're putting into your body. If you drank the same amount of water each of these days, you'd likely feel more fatigued on some days than others.

Likewise, your needs will vary if you have a chronic illness, or if you're menstruating, pregnant, or recovering from injury. Any number of things can change your body's basic functions, and thus your hydration needs!

Forget the 8-glass rule & try an improved formula

Seems like we're back to the original question, right? Well, even though we know that the old advice is outdated, and there's no perfect answer for anyone on Earth, there are a number of new formulas you can try.

For example, according to the University of Missouri, here's one formula for setting your daily water goal:^{2 3}

1. To calculate your minimum goal, divide your body weight in pounds by 2. That's the number of ounces of water you should drink daily.
2. On exercise days, add another 12 ounces for each 30 minutes of activity.

As you might notice, anyone who weighs more than 128 pounds should therefore be averaging more than 8 glasses of water –that is, 64 ounces– per day. (Using a standard cooking measurement of one cup, which is 8oz.)

The Last Word: Your body is a complex but intelligent machine

On the bright side, your body will always tell you if your daily water goal is too little. Be sure to track your water consumption, and pay attention to your thirst, fatigue, and concentration levels (not to mention the color of your urine!). Even without a fancy formula, you'll be able to interpret what your body is saying!

Regardless of your daily water drinking target, you might find it tough to drink as much water as you planned. Here's some extra advice to help you enjoy drinking water!