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Water Intake Calculator
Estimate how much water you may need each day from your body weight, activity level and exercise time.
Under 30 seconds
Updated 25 Sept 2026
Results
Estimated daily water intake
2.7 L/day
A general estimate of total daily water — not a medical requirement.
- Litres per day
- 2.7 L
- Glasses (250 ml)
- ≈ 11 glasses
- Weight used
- 70 kg
Base (35 ml × kg)
2,450 ml
Activity allowance
250 ml
Exercise allowance
0 ml
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</iframe>Water needs vary between people. This result is only an estimate — climate, exercise, diet and medical conditions can all change how much you need — and it is not medical advice.
This water intake calculator gives a general estimate: about 35 ml of water per kg of body weight, plus a small allowance for your activity level and about 350 ml for every 30 minutes of exercise. The result is shown in litres and 250 ml glasses. It is an estimate, not a medical requirement.
Visual breakdown
A visual view of your calculation.
Interactive charts arrive here soon.
Smart Insights
Generated from the numbers you entered — no guesswork.
- Estimate: 2,450 ml for body weight + 250 ml for activity + 0 ml for exercise ≈ 2.7 L/day.
- This figure covers total water, and part of it can come from food and other drinks.
- Water needs vary between people. This result is only an estimate — climate, exercise, diet and medical conditions can all change how much you need — and it is not medical advice.
What is the Water Intake Calculator?
What the tool does, who it is for and what it cannot tell you.
A water intake calculator gives a rough estimate of how much water a person may need in a day, using body weight and activity as simple guides.
Water needs vary because bodies differ in size, activity, sweat rate and diet. Hot or humid weather, long workouts and foods with high or low water content all change the number.
How does the Water Intake Calculator work?
Each step the calculator runs, in plain language.
- 1
Enter your weight
In kg or lb; pounds are converted to kilograms.
- 2
Choose activity and exercise
A small allowance is added for activity and for exercise minutes.
- 3
Read the estimate
Shown in litres per day and approximate 250 ml glasses.
What to enter in each field
The exact figure each input expects, so the result means what you think it means.
- Body weight
- Realistic adult weight; decimals are accepted.
- Activity level
- Your usual daily movement outside of planned exercise.
- Exercise
- Optional. Leave at 0 if you do not exercise that day (maximum 300 minutes).
Water Intake Calculator formula
The exact maths behind every number on this page.
Daily water (ml) = 35 × weight (kg) + activity allowance + 12 × exercise minutes
- weight (kg)
- Body weight in kilograms (1 lb = 0.45359237 kg)
- activity allowance
- 0, 250, 500 or 750 ml for sedentary, light, moderate or very active
- exercise minutes
- About 12 ml per minute, roughly 350 ml per 30 minutes
This is a simple general rule of thumb used for estimates, not a clinical formula. One glass is taken as 250 ml.
Water Intake Calculator calculation example
Hypothetical example: a 70 kg person, lightly active, exercising 30 minutes a day.
- 1Base35 × 70 = 2,450 ml
- 2Activity (light)+250 ml
- 3Exercise12 × 30 = 360 ml
- 4Total2,450 + 250 + 360 = 3,060 ml ≈ 3.1 L (about 12 glasses)
The estimate is about 3.1 litres a day. All figures are hypothetical.
Important assumptions
What this calculation includes, and what it leaves out.
- Baseline of 35 ml per kg of body weight, a common general estimate.
- Activity allowance of 0–750 ml and about 12 ml per minute of exercise.
- One glass = 250 ml. Unit conversion uses 1 lb = 0.45359237 kg.
- Water needs vary between people. This result is only an estimate — climate, exercise, diet and medical conditions can all change how much you need — and it is not medical advice.
Financial tips
Practical guidance to act on your result.
- Needs may be higher in hot weather, at altitude, during long or intense exercise, or when unwell with fever or vomiting.
- Some conditions and medicines (for example kidney or heart conditions) can change fluid needs — follow your doctor's guidance.
- Pregnancy and breastfeeding can also change water needs; ask a qualified professional.
Frequently asked questions
Short, direct answers to the questions we hear most.
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Disclaimer
CalPaisa calculators are for general information and planning only. Results are estimates based on the values you enter and standard formulas, and may differ from the figures your bank, employer, or tax authority applies. Nothing here is investment, tax, or legal advice. Please confirm important decisions with a qualified professional. Read our financial disclaimer, learn how CalPaisa works, or tell us about a calculation you think is wrong.