How much water should you drink a day?
“8 glasses for everyone” is a myth: needs depend on sex, movement and heat. We use the EFSA anchors — including the honest correction that part of your water arrives with food.
Total fluid ≈ 2.0 L, of which ~20% arrives with food. That’s about 6 glasses of 250 ml — spread through the day. If you like, drink a little less in the last couple of hours before bed — for fewer night-time trips.
Please note: drinking a little less before bed is about sleep comfort, not medical advice to restrict fluids. If you’re thirsty, hot, exercising, pregnant or on medication, drink as much as you need and follow your doctor’s guidance.
Source: EFSA 2010 (adequate intake: ~2.0 L/day women, ~2.5 L/day men, all fluids; ~20% arrives with food). Thirst and pale urine are the best home indicators. With heart or kidney disease, the target is set by a doctor.
How to use the result
How it works
The anchor is based on sex, activity and heat, minus the roughly 20% that arrives with food — soups, fruit and vegetables count too.
How to read the result
Also consider thirst, urine colour, heat and activity. There is no need to force water on a rigid schedule.
Limitations
With heart, kidney or liver disease, swelling or a prescribed fluid limit, follow your clinician's advice.
Related calculators
Take the short health-factor map and see how this connects to your own lifestyle.