Daily drink volume—
Choose your usual glass size.
The NHS Eatwell Guide says most people should aim for 6–8 cups or glasses of fluid a day, but this is only a guide. Tea, coffee, lower-fat milk and sugar-free drinks can count. You may need more when active for long periods, in hot weather, during pregnancy/breastfeeding or when ill. Some medical conditions require fluid limits, so follow clinical advice where relevant.
What this calculator does
It simply converts a cup count into millilitres and litres so the 6–8 glass guide is easier to picture. It does not attempt to prescribe an exact personal water requirement.
Built for quick, transparent estimates. See how our calculators work and check page-specific assumptions before relying on a result.