HydrationCalc: Water Goal

HydrationCalc estimates how much water you need in a day from three things that actually change the answer: your body weight, the activity you do and the climate you are in. Most guidance hands everyone the same figure. This gives you a number built from your own inputs, and it moves the moment you change one.

Enter your weight in kilograms, pick your activity level and how long it lasts, then pick the climate. The daily target appears at the top in litres, with the same figure in millilitres and US fluid ounces underneath. There is nothing to submit and nothing to set up first.

WHAT YOU CAN DO
- Get a daily water target from your body weight, at 33 mL per kilogram
- Add for training with four activity levels, from sedentary to heavy
- Set how many hours the activity lasts and watch the target rise with it
- Add for the weather with four climate settings, from cold to extreme heat
- Read the result in litres, millilitres and US fluid ounces at the same time
- See the figure recalculate live as you type, with no button to press
- Open the About screen for a one paragraph summary of the method
- Use it in light or dark appearance, on iPhone and on iPad

WHO IT IS FOR
People who train or work physically and want a target that reflects the session rather than an average. People living or working in heat, where a standard figure falls short. Anyone who has been told to drink more water and wants a real number to aim at rather than a rule of thumb.

PRIVACY
There is no account and no sign up. The app makes no network requests, so nothing you enter leaves your device and nothing is collected.

HydrationCalc is an informational calculator, not medical advice. It does not diagnose or treat anything and it does not replace a health professional. Speak to a qualified professional about your own fluid needs.