Pillar
Water Intake Calculator by Body Weight
Quick answer
Water Intake Calculator by Weight. Example: 70 kg, light activity, temperate climate: 2.6 L of beverages. This is a planning estimate.
Fine-tuneMeasure in bottles · Your day
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Your daily goal: 91 Ounces, 11 glasses.
Your daily goal
Updates instantlyof water a day · about 11 glasses · 5.5 half-litre bottles
Planning scenarios: 85-108 fl oz. Use it as a flexible target, not a medical limit.
Start
2 glasses
7:00 AM
Taper
9:00 PM
for better sleep.
Food fluid
+0.7 L
typical food water
- 2.7
- Litres
- 91
- Ounces
- 11
- glasses
Why this number
WaterDailyGoal uses 33 ml/kg for a beverage planning estimate. The 30–40 ml/kg scenarios and activity/climate coefficients are site assumptions, not validated personal requirements or NAM/EFSA formulas. Pregnancy, breastfeeding, and GLP-1 medicines do not automatically change this estimate. Population total-water references include food; they are not minimum drinking doses. Follow individual clinical advice.
Full methodologyNext step
Your sip schedule
- 7:00 AM · Start the day2 glasses
- 9:48 AM · Top up2 glasses
- 12:36 PM · Top up2 glasses
- 3:24 PM · Top up1.5 glasses
- 6:12 PM · Top up1.5 glasses
- 9:00 PM · Wind down1.8 glasses
Ease off after 9:00 PM for better sleep.
Electrolytes? Not automatic
Electrolytes are not automatic. Long or heavy sweating and vomiting or diarrhea need different approaches; food, losses and medical restrictions matter. Ask a clinician or pharmacist when illness is involved.
A friendly estimate for healthy adults, not medical advice. Your needs rise with heat, exercise, illness, pregnancy, and some medications. Don't drink more than ~1 litre per hour.
Your daily goal
91 fl oz
The link and preview image include your weight and settings.
Daily water by body weight (30-40 ml per kg)
WaterDailyGoal uses 33 ml/kg for a beverage planning estimate. The 30–40 ml/kg scenarios and activity/climate coefficients are site assumptions, not validated personal requirements or NAM/EFSA formulas. (kg × 0.030 + 0.3) … (kg × 0.040 + 0.3) L; ×1.0.
| Body weight | Low | High | Typical litres |
|---|---|---|---|
| 120 lb (54 kg) | 64 oz | 85 oz | 2.2 L |
| 140 lb (64 kg) | 74 oz | 95 oz | 2.5 L |
| 150 lb (68 kg) | 78 oz | 101 oz | 2.7 L |
| 160 lb (73 kg) | 85 oz | 108 oz | 2.9 L |
| 180 lb (82 kg) | 91 oz | 122 oz | 3.2 L |
| 200 lb (91 kg) | 101 oz | 132 oz | 3.5 L |
| 220 lb (100 kg) | 112 oz | 145 oz | 3.8 L |
| 250 lb (113 kg) | 125 oz | 162 oz | 4.3 L |
Why the calculator can differ from the chart
The chart is useful for body-weight lookup. The live calculator adds the day context that a static table cannot see.
| Day type | Inputs | Calculator goal | Why it moves |
|---|---|---|---|
| Desk day | sedentary, cool | 2.3 L · 78 oz | Lower sweat and cool climate |
| Normal day | moderate, moderate | 2.7 L · 91 oz | Baseline plus light activity |
| Workout in heat | active, hot | 3.3 L · 112 oz | Activity add-on plus heat multiplier |
| Hard training in heat | intense, hot | 3.7 L · 125 oz | Highest activity add-on; electrolyte cue |
The simple formula
WaterDailyGoal uses 33 ml/kg for a beverage planning estimate. The 30–40 ml/kg scenarios and activity/climate coefficients are site assumptions, not validated personal requirements or NAM/EFSA formulas.
Frequently asked
How much water should I drink based on my weight?
WaterDailyGoal uses 33 ml/kg for a beverage planning estimate. The 30–40 ml/kg scenarios and activity/climate coefficients are site assumptions, not validated personal requirements or NAM/EFSA formulas.
Is half my body weight in ounces accurate?
WaterDailyGoal uses 33 ml/kg for a beverage planning estimate. The 30–40 ml/kg scenarios and activity/climate coefficients are site assumptions, not validated personal requirements or NAM/EFSA formulas.
Sources
- 1.U.S. National Academies (IOM/NAM), 2005 — Adequate total water intake of about 3.7 L/day for men and 2.7 L/day for women, including water from food and all beverages.Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate, Summary: water adequate intakes; drinks and food
- 2.European Food Safety Authority (EFSA), 2010 — Adequate total water intake of 2.5 L/day for men and 2.0 L/day for women under temperate conditions.Scientific Opinion on Dietary Reference Values for water, EFSA Journal 8(3):1459, abstract and conclusions
- 3.Mayo Clinic — General guidance of roughly 2.7–3.7 L of total fluids a day, with thirst and pale-yellow urine as everyday checks.