Water intake calculator: how much water should you drink?

There's no single "right" number of ounces for everyone, but a body-weight guideline gives a reasonable starting point. Enter your weight below for a general estimate of a daily water goal, then let thirst and how you feel fine-tune it.

How the estimate is calculated

This calculator uses the same simple, widely-cited guideline Valune uses in the app: aim for roughly half your body weight, in fluid ounces, of water per day. So a 160 lb person lands around 80 oz — about 10 cups (an 8 oz cup). If you enter kilograms, we convert to pounds first. Valune keeps a sensible floor of 6 cups a day for lower body weights.

If you add exercise minutes, we nudge the estimate up by roughly 12 oz for every 30 minutes of activity — a rough general adjustment for fluid lost to sweat, not a precise measurement. Heat, altitude, illness, pregnancy, breastfeeding, and some medications and conditions all change your needs, and this simple formula can't account for them.

The number is a starting point, not a target to force. Your body's thirst is the better day-to-day guide.

Two honest signals that beat any calculator

• Thirst. For most healthy people, drinking to thirst does a good job of keeping you hydrated. You don't have to hit an exact ounce count to be fine.
• Urine color. Pale straw or light yellow generally suggests you're well hydrated; consistently dark yellow can be a sign to drink a bit more. It's a rough cue, not a diagnosis, and vitamins or certain foods can tint it.

Remember that water comes from food and other drinks too — fruit, vegetables, soup, tea, and coffee all count toward your fluids. The glass in your hand isn't the only source.

Why "needs vary" isn't a cop-out

A larger, very active person training in the heat genuinely needs far more fluid than a smaller person at a desk on a cool day. That's why a one-size number can mislead. Use the estimate to set a loose daily habit, then adjust with the signals above. If you're ever unsure — especially with a heart, kidney, or other medical condition that affects fluid intake — a clinician's guidance beats any formula.

Sources

• Daily water goal — ≈ half your bodyweight in ounces. Mayo Clinic — Water: How much should you drink every day?
• Fluid from food & other drinks and general hydration guidance — U.S. Centers for Disease Control & Prevention

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• Free vs paid health apps

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This calculator provides a general estimate for healthy adults and is for informational purposes only. Valune is a general wellness app, not a medical device, and does not diagnose, treat, cure, or prevent any medical condition. Your fluid needs depend on your body, activity, climate, and health. Talk with a qualified healthcare professional before making significant changes to your fluid intake, especially if you are pregnant or breastfeeding, or have a heart, kidney, liver, or other condition that affects how much you should drink.