Hydration Calculator
How much water should you drink a day?
Your personalised daily hydration target, and a Fuel24 plan to hit it.
How we calculate your hydration
Science-led, transparent and tunable
Your daily target adapts to your body, today's conditions and what you've already drunk. No one-size-fits-all "8 glasses".
The recipe
What feeds into your target
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01
Baseline need Personalised to your body weight, with a small adjustment for age.Your baseline
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02
Activity Low, medium or high movement increases your daily need.Movement boost
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03
Climate Hot conditions push it up, cool ones nudge it down.Climate factor
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04
Life stage Pregnancy and breastfeeding require additional fluid.Life-stage need
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05
Event or training Sport, duration and intensity, dialled in by you.Your input
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−
Food water Some of your daily hydration comes from food.Food share
Your daily fluid target
The drink index
Why drinks count differently
Caffeine and alcohol have a mild diuretic effect; electrolyte drinks and milk help retain water. We weight your declared intake accordingly.
WaterFull
Coffee & teaSlight discount
AlcoholDiscount
Electrolytes & milkBonus
Sources
Where the figures come from
- EFSA Scientific Opinion on Dietary Reference Values for Water (2010)Baseline, activity, climate & life-stage adjustments
- IOM Dietary Reference Intakes for Water, Potassium, Sodium, Chloride & Sulfate (2004)Climate & environmental adjustments
- ACSM Position Stand on Exercise & Fluid Replacement (2007)Sweat-loss rates by sport & intensity
- NHS UK — Water, drinks and your healthUK general hydration guidance
General guidance, not medical advice. For specific hydration needs, consult a healthcare professional.