Water Intake Calculator

Estimate daily water intake based on body weight, activity, climate, and hydration goal. This free water intake calculator supports US and metric units and shows practical daily water targets in cups, ounces, and liters.

Calculate Daily Water Intake

Using body weight in pounds and activity in minutes per day.
Using body weight in kilograms and activity in minutes per day.
Your result will appear here.

How water intake is estimated

Body weight first:
This calculator starts with a body-weight-based hydration estimate.

Exercise adjustment:
More activity can increase daily water needs.

Climate adjustment:
Warm or hot conditions can raise the target further.

Serving plan:
The result also shows how much water that may be per serving during the day.

Why water intake matters

Water supports temperature regulation, circulation, digestion, and many everyday body functions. A practical hydration target can make it easier to plan water intake through the day.

Many people find it easier to stay hydrated when they have a simple daily goal to follow.

What your result means

Your result shows an estimated daily water target in ounces, cups, and liters, along with a simple serving breakdown and activity-adjusted hydration estimate.

This gives you a practical daily hydration goal you can use throughout the day.

Water intake calculator tips

Frequently asked questions

How much water should I drink per day?

That depends on body size, activity, climate, and daily routine. This calculator gives a practical estimate based on those factors.

Do I need more water when I exercise?

Often yes. Sweating and longer activity can increase hydration needs.

Does coffee count toward hydration?

Many drinks can still contribute to hydration, though some people prefer to slightly raise water targets when caffeine intake is higher.

Is there one perfect water target for everyone?

No. Hydration needs can vary a lot based on body size, environment, diet, and activity.