Water Intake Calculator
Personal daily hydration target from weight, exercise, climate & life stage — with an hourly sipping schedule and PDF plan.
Your daily fluid target
2.80 litres/day
To drink
2.24 L
From food
560 ml
Glasses (250 ml)
9
🫗 Your target, in real containers
🥛
9
Glasses
250 ml each
☕
10
Cups
8 fl oz each
🍼
5
Small bottles
500 ml each
🧴
3
Sports bottles
750 ml each
🫙
3
Big bottles
1 litre each
🌍 How your target compares to official guidelines
U.S. National Academy of Medicine
3.70 L
total fluids, all sources · men
Your personalised target is 900 ml below this anchor.
EFSA (European Food Safety Authority)
2.50 L
total fluids, all sources · men
Your personalised target is 300 ml above this anchor.
Official values are population-wide adequate intakes — your personalised number adjusts for your body, activity, and climate.
⏰ Your hour-by-hour sipping schedule
| Time | Drink | Tip |
|---|---|---|
| 7:00 AM | 250 ml | On waking - rehydrate after the night |
| 8:53 AM | 250 ml | |
| 10:45 AM | 250 ml | |
| 12:38 PM | 250 ml | A glass before lunch also curbs overeating |
| 2:30 PM | 250 ml | |
| 4:23 PM | 250 ml | |
| 6:15 PM | 250 ml | |
| 8:08 PM | 250 ml | With dinner |
| 10:00 PM | 250 ml | Last glass - about an hour before bed |
Evenly spaced from wake-up, finishing about an hour before bed so sleep isn't interrupted.
⚠️ Educational estimate, not medical advice. Kidney, heart, or other conditions change fluid needs — follow your doctor's guidance if you have one.
💧A hydration plan, not just a number
This calculator builds your personal daily water target from your body weight (age-adjusted), exercise, climate, and life stage — then turns it into things you can actually use: how many glasses and bottles that is, how your number compares to official international guidelines, and an hour-by-hour sipping schedule from your wake-up time to an hour before bed, downloadable as a branded PDF.
📊Everything you'd want to know
- Base need from body weight — 35 ml/kg under 30, 33 ml/kg for 30–55, 30 ml/kg over 55.
- Exercise top-up of ~350 ml per 30 minutes of sport or training.
- Climate adjustment for hot-dry and hot-humid regions, plus pregnancy and breastfeeding add-ons.
- The ~20% of fluids that arrive through food, split out so you know what to actually drink.
- Comparison against the U.S. National Academy of Medicine and European EFSA adequate intakes.
- A realistic sipping schedule around your own wake and sleep times, in metric or fl oz.
🧮The science
Roughly 20% of daily fluid typically comes from food — fruit, rice, dal, curries, and vegetables all count — so your drinking target is about 80% of the total. Official anchors: the U.S. National Academy of Medicine suggests ~3.7 L/day for men and ~2.7 L for women from all sources; Europe's EFSA suggests 2.5 L and 2.0 L.
💡Habits that make it easy
- Drink a full glass right after waking — you lose water all night breathing and sweating.
- Keep a bottle on your desk; you drink 2–3× more when water is within arm's reach.
- A glass before each meal helps digestion and portion control.
- Urine colour is the honest check: pale straw = hydrated, dark yellow = drink up.
- Stop big drinks ~1 hour before bed so hydration doesn't cost you sleep.
💡 Frequently Asked Questions
How much water should I drink a day?+
A solid estimate is 30–35 ml per kg of body weight, plus about 350 ml for every 30 minutes of exercise, with more in hot climates. For a 70 kg person that's roughly 2.3–2.8 litres in total — this calculator personalises it and splits out what to drink vs what food provides.
Do tea, coffee, and juice count toward my water intake?+
Yes. All beverages contribute to hydration, and normal coffee or tea amounts do not dehydrate you. About 20% of your fluid also arrives via food. Water is still the best default because it carries zero sugar and zero calories.
Can I drink too much water?+
Yes — forcing several litres in a short window can dilute blood sodium (hyponatremia), which is dangerous. Spread intake across the day, guided by thirst and urine colour. This tool flags targets that look unrealistically high.
How much extra should I drink when exercising?+
A common guideline is about 350 ml for every 30 minutes of moderate exercise, taken before, during, and after the session. Intense sweating in hot or humid weather can need more — the climate setting adds that on top.
Does the target change during pregnancy or breastfeeding?+
Yes. Guidelines add roughly 300 ml/day during pregnancy and about 700 ml/day while breastfeeding, since milk production draws directly on body water. Select the life-stage option to include these.