Quick Answer
8 glasses of water is equivalent to about 2 liters of water. The recommended daily water intake is around 2 liters for women and 2.5 liters for men. Each glass typically holds 250ml to 300ml of water. So 8 glasses containing 250ml each would be 2,000ml or 2 liters.
How Big is a Glass of Water?
The size of a glass can vary significantly, so it’s hard to put an exact liter amount on “8 glasses” of water. Here are some typical glass sizes:
- Standard glass: 250ml
- Large glass: 300-350ml
- Small glass: 200ml
- Cup: 150-200ml
- Water bottle: 500ml
A standard 8 ounce glass holds about 240ml and a 12 ounce glass holds about 350ml. So glass size can range from 150ml on the small end up to 350ml for a large glass.
Recommended Daily Water Intake
Men
The Institute of Medicine recommends that men consume about 3 liters (13 cups) of total beverages a day. This includes water, other drinks and even food. The average recommended amount of just water is about 13 cups or 3 liters for men. A typical bottle of water contains 500ml, so the recommended daily intake is about 6 bottles of water.
Women
The recommended total fluid intake for women is 2.7 liters (11 cups) per day from all beverages and foods. The average recommended intake for just water is about 9 cups or 2.2 liters per day for women. The recommended amount of water for women is about 4.5 bottles per day.
8 Glasses Compared to Daily Recommendations
So how does 8 glasses stack up against the recommended daily intake?
- For men: 8 glasses of 250ml each is 2 liters. The recommended intake is about 3 liters, so 8 glasses only meets about two-thirds of the recommended amount.
- For women: 8 glasses of 250ml each is 2 liters. The recommended intake is 2.2 liters, so 8 glasses just meets the recommendation.
Eight 250ml glasses hits the recommended amount for women but comes up a little short for men. However, if the glasses are on the larger side, like 300ml each, then 8 glasses would exceed the recommended intake for both genders.
Benefits of Drinking Water
Why is it important to drink enough water each day? Here are some of the main benefits:
- Keeps body hydrated – Drinking water prevents dehydration, which can cause headaches, fatigue and poor concentration.
- Boosts exercise performance – Dehydration negatively impacts physical abilities. Drinking enough water is important for athletic activities.
- Supports kidney function – Water helps flush toxins from the kidneys and reduces kidney stone risk.
- Aids digestion – Water helps digest food and prevents constipation.
- Maintains fluid balance – Water is critical for fluid balance in the body’s cells, tissues and organs.
- Healthy skin – Staying hydrated provides moisture for the skin and reduces dryness.
In addition to these benefits, some research indicates that drinking more water may help with weight loss by increasing fullness and boosting metabolism slightly.
Tips for Drinking More Water
Here are some simple tips to help you drink enough water each day:
- Carry a water bottle – Having water always available makes it easier to sip throughout the day.
- Set reminders – Use an app or alerts to remind yourself to drink water at set intervals.
- Infuse with fruit – Add slices of lemon, lime, cucumber or watermelon to your water for flavor.
- Substitute sparkling water – The bubbles and flavors can make water more interesting.
- Drink before meals – Consuming water 15-30 minutes before meals can aid digestion and increase fullness.
- Choose water when eating out – Opt for water instead of sugary drinks when dining at restaurants.
Starting a water habit when you first wake up and drinking a glass before each meal is a good way to integrate more water into your daily routine.
Signs of Dehydration
It’s important to watch out for signs of dehydration, which occurs when the body loses more fluid than it takes in. Symptoms may include:
- Increased thirst
- Less frequent urination
- Dark yellow urine
- Dry mouth
- Fatigue
- Dizziness
- Headaches
Severe dehydration can lead to dire health outcomes, so it’s critical to pay attention to your fluid intake. Contact your doctor right away if you experience severe symptoms like rapid heartbeat, fever, confusion or inability to urinate.
Who May Need More Water?
While the standard recommendations are 2-3 liters per day, some individuals may need more fluid intake:
- Athletes or people who exercise regularly lose more fluids through sweat.
- People who live in hot climates are exposed to more fluid loss from heat and perspiration.
- Pregnant women need additional fluids to stay hydrated.
- People with certain health conditions like diabetes or kidney disease may require more fluid intake.
- Older adults often have reduced thirst perception so they need reminders to drink water.
Talk to your doctor about your individual fluid needs based on your health, medications, activity level and environment. They can provide customized recommendations.
Water Intake for Children
Hydration needs differ for children depending on their age group:
- Infants under 6 months only need breast milk or formula.
- Babies 6-12 months need 800-1200ml per day from breast milk or formula.
- Children 1-3 years old need about 4 cups or 1000ml daily.
- Kids 4-8 years old need 4-5 cups or 1200ml per day.
- Children 9-13 years old need 5-8 cups or about 1600ml each day.
Offer children water frequently with meals and snacks. Limit sugary juice and soda intake which can displace needed water consumption.
Daily Water Intake Recommendations
Here is an overview of the recommended daily water intake from food and beverages for different groups:
| Group | Recommended Total Water Intake |
|---|---|
| Men | 3.7 liters (15 cups) |
| Women | 2.7 liters (11 cups) |
| Pregnant Women | 3 liters (12 cups) |
| Breastfeeding Women | 3.8 liters (15 cups) |
| Infants 0-6 months | Only breast milk or formula |
| Infants 6-12 months | 0.8-1.2 liters (3-4 cups) |
| Children 1-3 years | 1.3 liters (5 cups) |
| Children 4-8 years | 1.6 liters (6 cups) |
| Children 9-13 years | 2.1 liters (9 cups) |
This covers total fluid intake from water, other beverages and food moisture. Aim to get at least half your daily fluid from plain water rather than other high-calorie drinks.
How Much Water Do You Need?
As a general guideline, aim for the following daily water intakes:
- Women: At least 9 cups (2.2 liters)
- Men: At least 12 cups (3 liters)
- Add 1 cup (240ml) for each hour of exercise or hot environment exposure
- An extra 1-2 cups (240-500ml) if you are sick, pregnant or breastfeeding
However, water needs can vary significantly based on your health, activity level, climate and more. Check with your doctor if you have concerns about your fluid intake. They can provide personalized recommendations.
Setting a Water Goal
To make sure you drink enough water, it can help to set a daily goal tailored to your needs:
- Calculate your recommended water intake based on your gender, activity level, health status, etc.
- Consider your diet – If you eat a lot of water-rich foods this contributes to fluid intake.
- Set an exact cup or ounce target based on your calculated needs.
- Break it into smaller intervals – such as every 1-2 hours drink one bottle.
- Use apps to track intake vs your goal.
- Carry a bottle and refill when needed to meet daily needs.
Having a specific water intake goal makes it more likely you will succeed. Adjust as needed based on thirst, urine color, exercise, and climate.
Signs You Are Drinking Enough Water
How can you tell if you are properly hydrated? Signs your water intake is adequate include:
- Clear or light yellow urine – Dark urine means you need more fluids.
- Regular bathroom trips – Going 4-6 times per day is healthy.
- Moist mouth and eyes – Dryness indicates dehydration.
- Good skin elasticity – Skin bounces back when pinched rather than staying tented.
- Few headaches or fatigue – Proper hydration prevents headaches.
- Muscle cramps are rare – Cramping with exercise may indicate dehydration.
- Normal bowel movements – Constipation can occur with inadequate fluid intake.
Pay attention to these markers in your body on a daily basis to monitor if you are drinking enough water. Increase your intake if any dehydration symptoms arise.
Downsides of Drinking Too Much Water
Is more water always better? Drinking excessive amounts can negatively impact health:
- Water intoxication – Extreme cases may dilute sodium levels critically.
- Headaches and urinary issues – Increased bathroom trips can disrupt sleep.
- Mineral depletion – Excess water flushes minerals like potassium from the body.
- Weight gain – More water increases fluid retention and weight until balance is achieved.
- Burden on kidneys – Kidneys must work harder to filter excess fluid.
Stick within the recommended daily intakes unless directed otherwise by your physician. Kidney function and sodium levels become especially important for chronically high water drinkers.
High Water Quality Matters
In addition to drinking enough water, it’s critical that your water comes from clean, safe sources:
- Tap water – Ensure your municipal supply meets safety standards.
- Well water – Test regularly for contaminants.
- Filters – Use charcoal filters to remove impurities.
- Plastic bottles – Avoid reusable bottles with BPA.
- Check taste – Bad tastes indicate dissolved metals or toxins.
Drinking contaminated water can negatively impact your health in the long-run. Be vigilant about filtering and testing home sources, as well as choosing BPA-free bottles.
Making Drinking Water Easy
Here are some tips to seamlessly increase your daily water consumption:
- Carry a water bottle – Having water on hand makes drinking convenient.
- Set hourly alerts – Apps can remind you to drink each hour.
- Front-load hydration – Drink 2-3 glasses first thing in the morning.
- Choose water with meals – Ask for water instead of sugary drinks.
- Infuse your water – Add fruits or herbs to enhance flavor.
- Cooler temperatures – Many people prefer chilled water.
- Straws make it easier – Using a straw helps some people drink more.
- Track your intake – Use apps to monitor daily consumption.
Developing simple habits like keeping water visible and setting reminders can help you effortlessly stay hydrated.
Frequently Asked Questions
Here are answers to some common questions about water intake recommendations:
How much water should I drink a day?
The recommended water intake is about 2 liters (8 glasses) for women and 3 liters (12 glasses) for men each day. This includes water from foods and other beverages. Thirst and urine color are the best guides.
What counts as water intake?
All beverages like milk, juice and tea count towards your fluid intake in addition to plain water. Even moist foods like fruits, vegetables, soups and yogurt contribute to hydration.
Do you need more water as you age?
Older adults may lose some sense of thirst so they should intentionally drink water even without feeling thirsty. Seniors may need to be reminded to drink adequate water each day.
Can you drink too much water?
Yes, excessive water consumption can potentially dilute sodium in the body to dangerously low levels. Stick to recommended intakes unless directed otherwise by your doctor. Moderation is key.
How much water should you drink before bed?
Limit fluid intake 1-2 hours before bedtime to avoid needing to urinate through the night. Consuming 8 ounces of water before bed is unlikely to cause waking at night for healthy adults.
The Bottom Line
Drinking enough water each day is essential for health. The recommended intake is around 2 liters (8 glasses) for women and 3 liters (12 glasses) for men. Listen to your body’s thirst signals and aim for light yellow urine. Water supports energy, digestion, skin health and much more. Develop habits like using a water bottle and setting reminders to ensure you stay well hydrated.
