Daily Water Intake Calculator & Habit Garden

A common guideline is 30–35 ml of water for every kilogram you weigh, plus extra when you are active, sweat a lot or the weather is hot. With JaxFit's activity extra, a 70 kg adult who is lightly active needs roughly 2.4 to 2.75 litres a day, about 11 glasses of 250 ml. Food provides some of your water too. Pale yellow urine is a simple sign you are drinking enough. If you have a heart or kidney condition, follow your doctor's fluid advice instead.

Water has no calories, helps you feel full and can make fasting windows easier by easing hunger pangs, which often feel similar to thirst. Drinking a glass before meals may help some people eat a little less. During a fast, water, black coffee and plain tea won't break it. Adding a pinch of salt is sometimes used on long fasts, but check with your doctor if you watch your salt intake.

Both are daily time-restricted eating plans. On 16:8 you fast for 16 hours and eat within an 8-hour window, for example noon to 8 PM. On 18:6 you fast for 18 hours and eat within 6 hours, for example 2 PM to 8 PM. 16:8 is the most popular starting point because it mostly uses the hours you are asleep. 18:6 adds two more hours in the fat-burning stage, but it is harder to keep up, so most people build up to it gradually from 14:10 or 16:8.

The World Health Organization classifies adult BMI (weight in kg divided by height in metres squared) as: below 18.5 underweight, 18.5 to 24.9 healthy weight, 25.0 to 29.9 overweight, and 30.0 or above obesity. BMI is a quick screening number, not a diagnosis: it doesn't measure body fat directly, so very muscular people can score high. For under-18s, BMI must be compared with growth charts for age and sex instead of these adult categories.

First your resting energy use (BMR) is calculated with the Mifflin-St Jeor equation: 10 × weight in kg + 6.25 × height in cm − 5 × age, plus 5 for men or minus 161 for women. That is multiplied by your activity level (1.2 for sedentary up to 1.9 for extra active) to give your TDEE, the calories you use in a day. For weight loss the calculator subtracts 250, 500 or 750 kcal depending on the pace you choose, but never suggests less than 1,200 kcal a day for women or 1,500 kcal for men.

Yes. Every calculation runs in your own browser. Your age, weight, goals, fasting timer and Habit Garden are saved only in your browser's local storage on this device, so they're there when you come back. Nothing is uploaded, there are no accounts, no analytics cookies, no tracking scripts and no ads. Clearing your browser data removes everything.