A common guideline is around 2 litres — about 6–8 glasses — of fluid a day, but your real need depends on your body size, activity level and climate. There's nothing magic about exactly eight glasses; the honest answer is "enough that you're rarely thirsty and your urine is pale." Here's the practical version.
The rough target
- ~2 litres (6–8 glasses) a day is a reasonable baseline for most adults.
- More if you're larger, active, sweating, or it's hot.
- Food counts too — fruit, vegetables and meals contribute a surprising amount of your fluid.
How to tell if you're drinking enough
The simplest check: pale yellow urine and rarely feeling thirsty means you're well hydrated. Dark urine, headaches or sluggishness can mean you need more. You don't need to obsess over a precise number.
Why it matters for your goals
- Fullness. Thirst is often mistaken for hunger — a glass of water before meals can curb overeating (how to stop overeating).
- Fibre needs it. If you're upping fibre, water is what makes it work without bloating (how to track fibre).
- Energy. Even mild dehydration saps focus and makes you feel hungrier.
Easy ways to drink more
Keep a bottle in sight, drink a glass with each meal, and flavour it if plain water bores you. Tea and coffee count (in moderation); sugary drinks add calories you don't need (how much sugar per day).
Track water with your day
forme lets you log water alongside your calories and macros — a simple tap to see whether you're on track, right next to everything else.
The bottom line
Aim for roughly 2 litres a day, more if you're active or it's hot, and use pale urine and low thirst as your real gauge. Food and tea count too. This is general information, not medical or dietary advice.