Daily Water Intake Calculator

Find out how many litres of water you should drink per day based on your weight and activity level.

Runs in browser
Daily water intake
litres / day

How Is It Calculated?

W = kg × 35 ml × factor

Base: 35 ml per kg of body weight. +15% for medium activity, +30% for high activity.

How to use?

  1. 1
    Enter body weightType your weight in kilograms.
  2. 2
    Select activity levelChoose low, medium, or high based on your daily physical activity.
  3. 3
    Read the resultYour recommended daily water intake in litres is shown.

FAQ

How much water should I drink per day?
The general guideline is 35 ml per kg of body weight. A 70 kg person needs about 2.5 litres per day. Activity, climate and health conditions can increase this.
Does coffee or tea count?
Moderate amounts of coffee and tea contribute to hydration. However, they have mild diuretic effects, so pure water remains the best source.
What happens if I drink too little?
Dehydration causes fatigue, headaches, difficulty concentrating and reduced physical performance. Even mild dehydration (1–2%) affects cognitive function.

How Much Water Should You Drink?

Water makes up about 60% of the adult body. Staying hydrated supports digestion, circulation, temperature regulation and cognitive function.

General Guidelines

  • Adults: 35 ml per kg of body weight per day
  • WHO recommends 2–3 litres/day for adults
  • Add 500 ml for every 30 min of intense exercise
  • Increase in hot climates or during illness

Signs of Dehydration

  • Dark urine or infrequent urination
  • Headaches and difficulty concentrating
  • Fatigue and dizziness
  • Dry mouth and skin

How How Much Water Should You Drink? is calculated

Searches for How Much Water Should You Drink? usually come from people who need more than a quick number. They want to understand the method, the assumptions and how the result should be interpreted. A useful article explains the formula in plain language, shows the inputs that matter, and makes clear that the result is an estimate. This is especially important for health and finance pages, where a small difference in input can change the conclusion.

What to check before using the result

Check the date, amount, rate, unit or personal value you entered. If a local rule, tax bracket, medical reference range or legal limit applies, make sure the current regulation is being used. Online tools are helpful for planning and comparison, but they should not replace a qualified professional when the result affects medical care, contracts, loans, payroll, taxes or legal obligations.

Local search intent

People may search for “How Much Water Should You Drink? calculator”, “how to calculate How Much Water Should You Drink?”, “How Much Water Should You Drink? online” or “free How Much Water Should You Drink?”. The page should therefore answer the direct calculation first, then explain the background, examples, limitations and next steps. Keep a copy of important results and confirm them with official documents or professional advice when necessary.

Examples, assumptions and responsibility

High-intent searches need more explanation because the result may influence planning, money or wellbeing. Always note which assumptions are used: period, rate, tax rule, reference range, unit, personal value or date. Run at least one realistic example and compare it with your own records. If the result seems surprising, do not force the number to fit; review the input and ask a professional when the decision matters.

FAQ

Can this replace professional advice? No. It is an educational calculator. Why is the result an estimate? Online tools simplify real life rules and may not know every local exception. How should I save it? Keep the input values, date of calculation and output together, especially for finance and health planning.

How How Much Water Should You Drink? is calculated

Searches for How Much Water Should You Drink? usually come from people who need more than a quick number. They want to understand the method, the assumptions and how the result should be interpreted. A useful article explains the formula in plain language, shows the inputs that matter, and makes clear that the result is an estimate. This is especially important for health and finance pages, where a small difference in input can change the conclusion.

What to check before using the result

Check the date, amount, rate, unit or personal value you entered. If a local rule, tax bracket, medical reference range or legal limit applies, make sure the current regulation is being used. Online tools are helpful for planning and comparison, but they should not replace a qualified professional when the result affects medical care, contracts, loans, payroll, taxes or legal obligations.

Local search intent

People may search for “How Much Water Should You Drink? calculator”, “how to calculate How Much Water Should You Drink?”, “How Much Water Should You Drink? online” or “free How Much Water Should You Drink?”. The page should therefore answer the direct calculation first, then explain the background, examples, limitations and next steps. Keep a copy of important results and confirm them with official documents or professional advice when necessary.

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