Free hydration planning tool
Choose how many cups or glasses you want to plan for and the approximate size of your usual drink. The calculator converts that into a daily fluid volume.
Your estimate
7 × 250 ml drinks = 1,750 ml across the day.
How to use the result
The point of this calculator is to make the general 6-to-8-drinks guidance easier to picture in litres. It does not use body weight, disease status or activity data to produce a medical recommendation.
If you are pregnant or breastfeeding, spend long periods exercising or in hot conditions, are unwell, or have a medical condition that affects fluid needs, general guidance may not fit your situation.
NHS guidance says water is a healthy, inexpensive choice, while lower-fat milk and sugar-free drinks, including tea and coffee, can also contribute to daily fluid intake.
Evidence basis
The NHS describes 6 to 8 cups or glasses a day as a general guide and explains situations in which people may need more fluid.
Read NHS guidanceThe Eatwell Guide includes 6 to 8 cups or glasses of fluid a day as general population guidance.
Read the Eatwell GuidePeople with medical conditions or special dietary needs should use advice from an appropriate healthcare professional rather than treating a general web calculator as personalised guidance.
Read our medical disclaimerEvidence checked: 18 August 2026.