WaterChamp

Yes. Coffee is a mild diuretic, but a normal cup brings in more water than the extra urine it causes. Black coffee has a hydration factor of 1.00 in the app, so a 240 ml cup adds 240 ml to your goal. A latte counts 1.10, because your body keeps milk a little longer than plain water. The app tracks the caffeine separately, on its own curve.

No. Black tea and green tea both have a hydration factor of 1.00, the same as water. A cup of tea also holds far less caffeine than a cup of coffee, so the fluid easily covers the small diuretic effect.

It depends mostly on your body weight. WaterChamp starts at about 26 ml per kilogram, then adjusts for age, sex, activity level and climate. It adds more during pregnancy or breastfeeding. A 70 kg adult with an average day lands near 1,800 ml. Work out your own number with the water intake calculator at https://waterchamp.app/tools/water-intake/.

It depends on how fast you clear caffeine. The half-life is about 5 hours for most people. It is near 3 hours if you clear it fast, and up to 8 hours if you clear it slowly. Half of a 3 pm coffee remains at 8 pm. The app models that curve and shows your last chance for coffee each day. Find your own cut-off with the caffeine cut-off calculator at https://waterchamp.app/tools/caffeine-cutoff/.

Partly, and the factor differs per drink. In the trial behind these numbers, a 4% lager finished level with still water, so beer counts 1.00. A pint is mostly water, and the volume covers the alcohol. Wine counts 0.50 and spirits count 0.00, because the same alcohol arrives in far less liquid. Every drink lists its own factor in the drink guide at https://waterchamp.app/drinks/.

Yes. The app writes your water and caffeine to Apple Health on iPhone, and to Health Connect on Android. The app writes alcohol to Apple Health only, because Health Connect has no alcohol record type. It also reads your workouts and sleep. Your goal rises by a millilitre per calorie you burn, and your hydration drops more slowly overnight.

Yes, the app is free to download and use. Logging any of the 102 drinks, your daily goal, today's progress and the widgets cost nothing. A Pro subscription adds the calendar and the full history, the caffeine and alcohol charts, and your own custom drinks.

The app has home screen and lock screen widgets in both sizes. They show today's progress, so you can check it without opening the app. The Apple Watch app is planned after launch.