How muchwateris your day?
Find your estimated daily water intake in seconds.
Daily estimate
0L
28yr
70kg
170cm
Your daily estimate
0L
≈ 0
cups
≈ 0
× 300 ml glasses
≈ 0
× 750 ml bottles
Your day in water
An illustrative sip rhythm totaling about 2.1 L. Adjust to your thirst, climate, and activity. Not a prescription.
07:30
Morning
About one focused drink.
300ml
10:30
Mid-morning
About one focused drink.
350ml
13:00
Lunch
About one focused drink.
450ml
16:00
Afternoon
About one focused drink.
350ml
19:00
Dinner
About one focused drink.
450ml
21:30
Evening
About one focused drink.
250ml
Running total ≈ 2.1 L across the day
~60%
of an adult body is water
Your body is mostly water
Brain and heart are closer to 73% water. Muscle holds more than fat. That is why hydration affects focus, temperature, and how you feel after a long day.
The percentage is an average for adults. Exact values vary with age, sex, and body composition.
What changes your water needs?
Daily intake is personal. Size, movement, heat, and health all shift how much you need.
Body
Larger bodies typically need more fluid to keep circulating volume and temperature stable.
Movement
Sweat loss climbs with intensity. Training days often need an extra glass or two beyond a desk day.
- Low
- Moderate
- High
- Very high
Heat
Hot or humid air raises sweat rate even when you are not exercising. Cool, dry rooms usually need less.
+ climatePlan an extra bottle on travel days and summer afternoons.
Environment
Altitude, dry indoor air, and long flights increase fluid loss. Cabin humidity is often very low.
Health and life stage
Pregnancy, breastfeeding, fever, and some medications change requirements. Talk with a clinician when needs feel unclear.
Balance
Hydration is not about drinking as much as possible. It is about matching intake to loss.
DehydratedDark urine, thirst, fatigue
BalancedPale yellow, steady energy
Too muchClear urine, bloating, rare risk
Too little
Mild dehydration can blunt focus and mood. Severe loss needs medical care. Learn dehydration signs.
Too much
Overdrinking can dilute sodium (hyponatremia). Listen to thirst, especially during long endurance efforts with heavy sweat loss.
How much water should you drink in a day?
The National Academies of Sciences, Engineering, and Medicine publishes adequate intake values for total water. That means plain water plus other beverages and the moisture in food.
Treat these as baselines, not prescriptions. Activity, climate, and health shift the target. Use the calculator for a personal estimate, then follow thirst.
Adequate intake, adults
Adults, men
3.7L
125 fl oz
About 15.5 cups from all fluids
Adults, women
2.7L
91 fl oz
About 11.5 cups from all fluids
By age
Ranges reflect growing bodies. Values still include moisture from food and other drinks.
| Age | Liters | Fluid ounces |
|---|---|---|
| 1-3 years | 1.3-2.1L | 44-72 oz |
| 4-8 years | 1.7-2.4L | 57-81 oz |
| 9-13 years | 2.4-3.3L | 81-112 oz |
| 14-18 years (boys) | 3.3-3.7L | 112-125 oz |
| 14-18 years (girls) | 2.3-2.7L | 78-91 oz |
Source framing: general adequate intake guidelines. Individual needs vary. Seek clinical advice when you have kidney disease, heart conditions, or other fluid restrictions.
Convert water volumes
Edit either side. Values update instantly.
Everyday measures
Tap a unit to see how it relates to milliliters.
1 Liter = 1000 ml
Convert liter to milliliters