Water Intake Calculator

Units

Metric active.

Sex (for reference AIs)

Weight kg

Active minutes/day

Adds ~350 ml per 30 min.

Climate/Temp

Waking hours

For an hourly plan.

Glass size ml

Pregnancy

Upper hourly cap

Safety reminder in schedule.

Daily Water Target (fluids)

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Glasses & Bottles

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Based on your glass size & 500 ml bottle.

Hourly Plan

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Your target vs general adequate intake (reference).

How we estimate your intake

Baseline: ~35 ml per kg body weight (≈0.5 oz per lb).
Activity: +350 ml per 30 minutes of exercise.
Climate: +0.5 L (warm) or +1.0 L (hot).
Pregnancy/Breastfeeding: +0.3 L / +0.7 L.
Reference AIs: ~2.7 L/day (women), ~3.7 L/day (men) total water from all sources; beverages typically ~80% of that.

Needs vary by body size, diet, meds, and health status.

Trust & Safety Note: This calculator is not a medical device. If you have a health condition or are pregnant, seek personalised advice from a qualified professional.

Water Intake Calculator – How Much Water Should I Drink a Day?

One-line intro: Find your personalised daily water target based on weight, activity, climate, and pregnancy/breastfeeding status — free, mobile-friendly.

What does this water intake calculator do?

It estimates your daily fluid goal using a weight-based baseline (~35 ml/kg) and adjusts for exercise, climate, and pregnancy/breastfeeding. You also get a per-hour plan, glasses/bottles equivalent, and a comparison to general adequate intake references.

How much water should I drink a day?

There’s no single number for everyone. A practical approach:

Baseline: ~35 ml per kg body weight (≈ 0.5 oz per lb).
Exercise: Add ~350 ml per 30 minutes of activity.
Climate: Add 0.5 L (warm) to 1.0 L (hot).
Pregnancy/Breastfeeding: Add 0.3–0.7 L.

General reference (all water from drinks + food): about 2.7 L/day (women) and 3.7 L/day (men). Beverages are typically ~80% of that total.

How to use the calculator (quick steps)

Choose units (Metric/Imperial).
Enter your weight and active minutes/day.
Select climate and (if applicable) pregnancy/breastfeeding.
Set waking hours and glass size for a practical plan.
Click Calculate to see your daily target, glasses/bottles, and hourly plan.

What counts toward water intake?

All beverages count (water, sparkling water, milk, tea/coffee, etc.).
High-water foods (fruit/veg, soups) contribute to total water.
For most people, plain water is the simplest way to hit targets.

Tips to stay hydrated (and avoid overdoing it)

Keep a reusable bottle nearby and sip steadily across the day.
Use reminders around meals, workouts, commuting, and bedtime.
In hot weather or long exercise, consider electrolytes.
Avoid very large intakes in a short time; spread fluids out to reduce discomfort and the risk of overhydration.

FAQs

Q: How much water should I drink a day?
Use the calculator: it combines weight, activity, climate to give a personalised number. Many adults land around 2–4 L/day, but needs vary widely.

Q: Daily water intake calculator vs “eight glasses a day”?
“8×8” (about 2 L) is a simple rule, not personalised. This tool adapts to your size and lifestyle.

Q: How much water to drink to lose weight (calculator)?
Hydration can support appetite control and exercise, but fat loss comes from a calorie deficit. Pair this with a calorie/TDEE calculator.

Q: Do coffee and tea count?
Yes, the water in them counts for most people. If caffeine affects you (e.g., diuretic effect, sleep), balance with plain water.

Q: How often should I drink?
Spread intake across waking hours (your result shows an hourly plan). Increase around workouts and hot conditions.