There’s no mistake that drinking plenty of water is one of the most important components of a healthy life. Not only does it keep us hydrated, but it also flushes out our bodies, keeping us feeling good and bloat-free. But how much water do we really need to drink? Many people have said that 8 glasses a day is the recommended amount, but the answer’s not that simple (and, by the way, a “glass” is not a unit of measurement).

There are several factors to consider when figuring out how much water to drink each day.

1. Your diet

Water isn’t just found in the tap! It’s also in the food we eat. If you’re getting some of your water from your diet, you may not need to drink as much as you might think. Other beverages, as well as fruits and veggies, all have water in them.

2. Your activity level

There’s no need to hydrate like an athlete if you aren’t one. At rest, your body needs less water than it does during a workout. A simple way to figure out how much you need on a low-activity day, according to US News & World Report Health, is this: divide your body weight by 2, and that’s how many ounces of water you need to drink. If you weigh 150 pounds, that’s 75 ounces of water.

3. The weather

If it’s a really hot day, you’re likely losing some of the moisture in your body by sweating. These are the days you need to up your water intake. If it’s a cooler day, you don’t need as much.

4. Your health

If you’re ill, fluids can be a big help, especially if you’re vomiting. This can make your body lose fluids quickly and you may not even realize it. Keeping your body well hydrated is very important in these situations, as dehydration can happen quickly and can further deteriorate your health. If you’re having trouble keeping liquids down, make sure you see a doctor.

So what can you do to determine how much water you need?

1. Pay attention to your thirst

Your body is probably a pretty reliable gauge of your hydration level. If you need more water, your body will likely tell you. Just make sure that some of your liquid intake is, in fact, water, as opposed to other beverages.

2. Check your urine

The clearer your pee, the more hydrated you are. If your urine starts getting darker or more yellow than you’re used to, drink some water. Another related indicator is how often you use the restroom. The more you drink, the more often you need to go. If it’s been a while, drink something.