Daily Water Intake Formula Explained, With Examples
Every daily water intake result comes from one formula. Once you understand what goes into it, you can sanity-check any figure you are given, whether by an employer, a bank, a teacher or another website.
The formula
About 33 ml per kg of body weight plus 350 ml per 30 minutes of exercise.
What each input means
- Weight (kg): the value you enter in the calculator.
- Exercise minutes a day: the value you enter in the calculator.
Example
For example, with these inputs:
- Weight (kg): 65
- Exercise minutes a day: 30
the calculator returns:
- Suggested water intake: 2.50 litres
How the result changes
The table keeps the other inputs at their example values and changes weight (kg).
| Weight (kg) | Suggested water intake |
|---|---|
| 65 | 2.50 litres |
| 32.5 | 1.42 litres |
| 48.75 | 1.96 litres |
| 81.25 | 3.03 litres |
| 97.5 | 3.57 litres |
Why it matters
Health numbers are most useful when you track them consistently. A quick calculation turns everyday measurements into something you can act on, whether that is planning meals, training for a run or preparing for a clinic visit.
Programmes such as the National Steps Challenge and the Healthy 365 app have made tracking activity common. Turning those numbers into distance, pace or calories helps set realistic goals for events like IPPT or a 10 km run.
Any health calculator gives a general estimate. If a result worries you, or you are pregnant, managing a chronic condition or planning a big change in diet or exercise, speak to a doctor, polyclinic or dietitian.
Research has shown that Asians tend to develop conditions such as type 2 diabetes and heart disease at lower body weights than Europeans. That is why the Health Promotion Board recommends lower BMI cut-offs for Singaporeans, with 23 marking the start of moderate risk.
Related calculations
- Calories Burned Calculator: Estimates calories burned with MET values.
- BMI Calculator (Asian Cut-offs): Singapore's Health Promotion Board uses lower BMI cut-offs for Asians because health risks rise at lower BMIs.
- BMI Calculator (WHO): Calculates BMI with the international WHO categories.
- BMR Calculator: Estimates calories your body burns at rest.
Use the Daily Water Intake Calculator to plug in your own numbers.
Run your own numbers: Daily Water Intake Calculator