Free tool
Water intake calculator
“Eight glasses a day” is a number with no evidence behind it. Your actual need scales with your bodyweight, how much you sweat and how hot it is where you live.
Where the numbers come from
The baseline is about 35 ml per kilogram of bodyweight, which is the figure most clinical guidance converges on for healthy adults.
Exercise adds roughly 500 ml per hour of training. Hot or humid conditions add another 500 ml or so across the day, warm conditions about half that.
Food contributes 20–30% of most people’s fluid intake, and tea, coffee and milk all count toward the total — the idea that caffeine dehydrates you does not survive contact with the evidence at normal intakes.
Simpler than a target
Just check the colour.
Pale straw means you are fine. Dark yellow means drink more. Completely clear means you are probably drinking more than you need, which is harmless but unnecessary.
Thirst is a reliable signal for most healthy adults under normal conditions. The main exceptions are older adults, whose thirst response blunts with age, and anyone training hard in heat.
One practical note for anyone tracking calories: sweetened drinks are where a startling number of unlogged calories hide. A day of sweetened chai, juice and a soft drink can quietly reach 500 calories.
Frequently asked questions
Do tea and coffee count?
Yes. At normal intakes the mild diuretic effect of caffeine does not offset the fluid in the drink. Milk, juice and soft drinks all count too — though the latter two bring calories with them.
Does drinking water help with weight loss?
Indirectly. A glass before a meal modestly reduces how much people eat, and thirst is sometimes misread as hunger. Water itself does not burn fat.
Can you drink too much water?
Yes, though it is rare. Drinking several litres in a short period can dilute blood sodium dangerously. Spread intake across the day rather than in large bursts.
Does BetterCal track water?
No, deliberately. Water logging is one of the small frictions that makes tracking feel like a chore, and it does not affect your calorie or macro numbers. BetterCal focuses on food.
Next step
Food is the part worth tracking.
Free to start on iPhone and Android.
