Daily Water Intake Calculator

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Find out exactly how much water you should drink each day. This calculator factors in your body weight, activity level, and environment to give you a personalized daily hydration target.

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Enter Your Measurements

Results

Daily Water Target

108

oz

Daily Water Target

3.2

liters

8 oz Cups Per Day

14

cups

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Formula

Base = Weight (lbs) × 0.5 oz; Activity add: Moderate +12oz, Active +24oz; Climate add: Warm +8oz, Hot +16oz

How to Use This Calculator

How to Use

  1. 1

    Enter your body weight.

  2. 2

    Select your typical activity level.

  3. 3

    Select your climate/environment.

  4. 4

    Drink the recommended amount spread throughout the day.

Frequently Asked Questions

Frequently Asked Questions

Does the 8 glasses a day rule apply to everyone?

The '8×8' rule (eight 8oz glasses = 64oz) is a rough average. Actual needs vary significantly by body size, activity, heat, and whether you eat water-rich foods. Larger people, athletes, and those in hot climates need considerably more.

Does coffee and tea count toward daily water intake?

Yes — caffeinated beverages contribute to hydration. A small diuretic effect exists but is offset by the water content. Aim for plain water as your primary source but don't subtract coffee or tea from your total.
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In-Depth Guides

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About This Calculator

This calculator uses the formula: Base = Weight (lbs) × 0.5 oz; Activity add: Moderate +12oz, Active +24oz; Climate add: Warm +8oz, Hot +16oz. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.

Built and maintained by the CalcSmart team. Last updated March 2026.

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