Estimate daily hydration needs based on body weight, activity, climate, and hydration habits. This free hydration calculator supports US and metric units and shows practical daily fluid targets in ounces, cups, and liters.
Body weight first:
This calculator starts with a body-weight-based fluid estimate.
Exercise adjustment:
More activity and sweat usually increase hydration needs.
Climate and sweat rate:
Warm weather, hot weather, and heavy sweating can raise the target.
Serving plan:
The result also shows a per-serving and per-hour hydration breakdown.
Hydration supports temperature control, circulation, digestion, and everyday physical function. A practical daily fluid target can make it easier to build a consistent hydration routine.
Many people do better with hydration when they have both a total goal and a simple daily schedule.
Your result shows an estimated daily fluid target in ounces, cups, and liters, plus a serving breakdown and hourly hydration guide.
This gives you a practical hydration target you can use throughout the day.
That depends on body size, activity, climate, and routine. This calculator gives a practical estimate using those factors.
Often yes. Longer exercise and heavier sweating can increase fluid needs.
Many drinks can still contribute to hydration, though some people prefer to slightly raise their water target when caffeine intake is higher.
No. Hydration needs can vary a lot based on body size, temperature, diet, activity, and sweat rate.