Where 2.3 litres and the higher moderate figure both come from
70 × 0.033 is 2.31, which the calculator copy rounds to about 2.3 litres. That sentence is the base, before activity. Choosing Moderate on the form multiplies by 1.2.
The 0.033 factor is a rule of thumb, about 33 millilitres per kilogram. It ignores weather, food, illness, and advice you have already been given about fluids.
The result is not “drink this many litres of plain water”
Food and other drinks also contribute fluid. The page does not subtract them. Adding the full result on top of a normal diet can overshoot what you need.
People who have been told to limit fluids, including some kidney and heart conditions, should follow that personal advice. More is not automatically safer.
Weight has to be in kilograms
The factor is for kilograms. Pounds will inflate the result. Convert first. The unit converter can turn pounds into kilograms. It cannot turn the water result into a prescription.
BMI uses the same kilogram weight plus a height. The two pages answer different questions and should not be blended into one health score.
Questions
Why does Moderate show more than the 2.3 litre example?
The example is the base, weight times 0.033. Moderate multiplies that base by 1.2.
Should I drink exactly the result?
No. It is a general estimate for learning the formula. Thirst, climate, and a clinician’s advice can override it.
Does the page include water in food?
No. It only multiplies weight by 0.033 and by the activity factor.