Water Intake Calculator

📖 Tool Introduction

The Water Intake Calculator helps you estimate how much water you should drink each day based on your body weight, your usual activity level and the weather outside. Many people either drink far too little all day, or habitually gulp a huge glass in one go, and neither habit is kind to proper hydration. This tool starts from a baseline of roughly 35 ml per kilogram of body weight, then multiplies it by adjustment factors for exercise intensity and air temperature, rounding the result to the nearest 50 ml so you get a daily target you can actually follow. It also converts that millilitre goal into a number of cups using the cup size you specify, and spreads the whole day's target across ten timed slots from seven in the morning to half past eight at night, reminding you exactly how much to drink at each moment so you are never left waiting until you feel thirsty. The result further shows the total in litres and the millilitres per kilogram, which makes it easy to compare against the hydration rules in fitness or weight-loss plans. It is a lightweight health tool that runs entirely in your browser and collects no personal data at all. You can reuse it across seasons: raise the weather factor on a scorching afternoon, lower it on a cool rainy day, and adjust the activity factor on rest days versus gym days. The cup-count display removes the mental arithmetic of how many glasses to finish, and the timed schedule turns an abstract daily number into small, reachable commitments every couple of hours, which is the part most people actually forget to do.

✨ Key Features

• Three-factor estimate: weight as the base, then activity and weather factors layered on top
• Automatic cup conversion: turns the millilitre goal into cups using your chosen cup size
• Timed drinking plan: splits the daily goal across ten slots from 7:00 to 20:30
• Multi-unit display: shows millilitres, litres and millilitres per kilogram together
• Copy and download: send today's plan to your notes or save it as a file
• Fully offline: no network access and no upload of body data, so privacy is protected

📝 How to Use

1. Type your weight in kilograms into the weight field
2. Choose your daily activity level and the current weather
3. Adjust the cup size to match the mug you actually use
4. Click Calculate to see your daily target and the timed schedule
5. Click Example to load 65 kg of default data and try it instantly

⚠️ Notes

• Health guidance: the result is general reference; pregnant women and people with kidney or heart conditions should follow their doctor's advice
• Weight range: enter a realistic weight; extreme values give unrealistic targets
• Small sips: spread the day's target across the slots rather than drinking heavily at once
• Cup size: the default is 250 ml; change it to 200 or 350 ml to match your cup
• Floor: the result never drops below 500 ml, so very light weights still get a sensible target