Fitness

Water intake calculator

Estimate your daily water needs based on weight, activity level, and climate.

Body weight (kg)

Activity level

Climate

—Litres / day

—mL / day

—8-oz cups

100% private. All processing happens locally in your browser — no files or data are ever sent to a server.

How to use Water intake calculator

01 Fill in the required values using the fields provided
02 Results calculate automatically as you type
03 Copy or note the result — all calculations stay on your device

Frequently asked questions

Common questions about Water intake calculator.

Is Water intake calculator free to use?

Yes, Water intake calculator is completely free. No account, subscription, or payment is ever required — just open the page and start using it.

Does Water intake calculator upload my data to a server?

No. Water intake calculator runs entirely in your web browser using client-side JavaScript. Your files, text, and data never leave your device, making it 100% private.

Can I use Water intake calculator on my phone or tablet?

Yes. Water intake calculator is fully responsive and works on all modern smartphones, tablets, and desktop browsers without installing any app.

Are these results accurate enough to rely on?

Water intake calculator uses well-established formulas and provides accurate estimates for everyday use. For financial, medical, or legal decisions, always consult a qualified professional.

More Fitness tools

Body fat calculator

Estimate body fat percentage using the US Navy measurement method. Supports metric and imperial inputs.

Fitness

One rep max calculator

Estimate your 1RM from a sub-max set using the Epley formula. Includes a full loading percentage table.

Fitness

Pace calculator

Calculate running pace, finish time, or distance from any two known values. Includes race finish time estimates.

Fitness

About Water intake calculator

The Water Intake Calculator estimates how much water you should drink per day based on your bodyweight, activity level, and climate. The widely cited advice of '8 glasses a day' is a rough generalisation — actual hydration needs vary considerably by individual, with factors including exercise sweat loss, ambient temperature, diet water content, and health conditions all playing a role. A common baseline is 35ml per kg of bodyweight per day, with an additional 500ml recommended per hour of moderate exercise. All calculations run locally and no personal data is stored.