Why your water goal is personal
There's no single number that fits everyone. A larger body needs more water than a smaller one, and every half hour of exercise or a hot day adds to what you lose through sweat. That's why this calculator starts from your weight and then adds extra for activity and climate, instead of using the old "8 glasses a day" rule for everyone.
How the calculator works
Your base goal is about 33 ml per kg of body weight. We add about 350 ml for every 30 minutes of exercise, 500 ml for hot or humid weather, and extra if you're pregnant or breastfeeding, in line with EFSA guidance. The result is rounded to a friendly number and shown in milliliters, liters, ounces and 250 ml glasses.
Simple ways to drink more water
Keep a bottle where you can see it, drink a glass with every meal, and set small checkpoints through the day, like half your goal by lunch. Tracking helps more than you'd think: seeing your progress fill up is surprisingly motivating.
Track it without an app store
Our Water Tracker is a web app: it opens in your phone's browser and lives on your Home Screen like any app, with no download, account or subscription. Tap a glass, watch the bottle fill and keep your streak going.