Metric formula guide
Water Intake Per kg Formula
Quick answer
Use this page for the metric formula, not the pound shortcut. A practical rule is 30–40 ml per kg of body weight per day. For a 70 kg adult, that is about 2.1–2.8 litres. Use the lower end for cool, sedentary days and add more for training, hot weather, pregnancy, breastfeeding, illness, or heavy sweating.
Fine-tuneMeasure in bottles · Your day
Saved profile
Save this setup to resume tomorrow on this browser.
Your daily goal: 2.6 litres, 10.5 glasses.
Your daily goal
Updates instantlyof water a day · about 10.5 glasses · 5 half-litre bottles
Planning scenarios: 2.4-3.1 litres. 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
- 2.6
- Litres
- 88
- Ounces
- 10.5
- 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 up1.5 glasses
- 3:24 PM · Top up1.5 glasses
- 6:12 PM · Top up1.5 glasses
- 9:00 PM · Wind down1.9 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.
Daily goal
2.6 litres
The link and preview image include your weight and settings.
Per-kg water chart
| Body weight | Low end | High end | Glasses |
|---|---|---|---|
| 50 kg | 1.5 L | 2.0 L | 8 |
| 60 kg | 1.8 L | 2.4 L | 10 |
| 70 kg | 2.1 L | 2.8 L | 11 |
| 80 kg | 2.4 L | 3.2 L | 13 |
| 90 kg | 2.7 L | 3.6 L | 14 |
| 100 kg | 3.0 L | 4.0 L | 16 |
Why this site starts near 33 ml/kg
The calculator uses about 33 ml/kg as a steady middle baseline, then adds activity, climate, and life-stage adjustments. That keeps the default realistic without pretending body weight is the only variable.
Frequently asked
How much water per kg of body weight should I drink?
A practical metric range is 30–40 ml per kg of body weight per day. For a 70 kg adult, that is about 2.1–2.8 litres before activity, heat, pregnancy, breastfeeding, or heavy sweat adjustments.
Is 35 ml per kg a good formula?
Yes, 35 ml/kg is a useful middle estimate for many healthy adults. This site uses about 33 ml/kg as the baseline, then adds activity and climate adjustments.
Should athletes use more than 40 ml per kg?
Often yes on training days. Athletes should add session fluid based on sweat rate instead of relying only on a per-kg daily rule.
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.