💧 Water Intake Calculator

Calculate your daily water intake based on weight and activity.

Calculate Now

What is Water Intake Calculator?

Most generic advice tells everyone to drink "8 glasses a day," but actual fluid needs scale with body size and how much you sweat. This calculator personalises that number using your body weight and activity level, giving you a daily litre target and its equivalent in glasses so you can track it through the day without carrying a measuring jug around.

Water Intake Formula

Daily Water (litres) = Weight in kg × 0.033 × Activity Multiplier
Glasses per day = Litres ÷ 0.25

The activity multiplier rises to roughly 1.4 for people who sweat regularly through exercise or physically demanding work, compared with a baseline multiplier for a more sedentary day.

Worked Example

For a 65 kg person who is moderately active:

Litres = 65 × 0.033 × 1.4 ≈ 3.0 litres
Glasses = 3.0 ÷ 0.25 = 12 glasses

That works out to about 12 standard 250 ml glasses spread across the day — noticeably more than the generic "8 glasses" rule, because it accounts for extra fluid lost through sweat.

How to Use This Calculator

  1. Enter your body weight in kilograms.
  2. Click Calculate.
  3. View your suggested daily water intake in both litres and glasses.

Things to Keep in Mind

This is a general guideline, not a strict medical prescription — hot, humid Indian summers, intense workouts, fever, or breastfeeding all raise fluid needs beyond this baseline, while certain heart or kidney conditions may require a doctor-specified fluid restriction instead. Spread intake evenly through the day rather than gulping it all at once, and let thirst and urine colour (pale yellow is a good sign) guide you between calculations.

💡 Tip: Water-rich foods like cucumber, watermelon, buttermilk (chaas), and dal also count toward your daily fluid total — you don't need to hit the number from plain water alone.

Pair this with the Protein Intake Calculator to round out your daily nutrition targets.

📅 Last reviewed: July 2026 · Formulas verified against RBI/SEBI/IT Dept guidelines.