Water by Weight Calculator
Enter weight and ml per kg. 70 × 30 give 2100 ml. 80 × 33 give 2640 ml. 60 × 35 give 2100 ml. The calculator multiplies and rounds millilitres. That is not 33 ml plus training from the water page.
Results
Enter data and click Calculate.
Not a clinic verdict. The result is ml = kg × ml/kg. You enter the factor. A fixed 33 and an effort add-on are on the water requirement page. The same day in glasses: how many glasses of water a day.
How it works
Water and weight in this calculator is mass in kg times a ml-per-kg factor. 70 × 30 = 2100. The script rounds to an integer. Without Format the result is 2100 ml. 80 × 33 = 2640 ml. 60 × 35 = 2100 ml, the same 2100 from another pair.
Field a is weight. Field b is ml per kg, not a fixed 33. 30, 33, or 35 stay what you type. The calculator does not add 350 ml for training.
The water page at 70 kg with no add-on computes 70 × 33 = 2310 ml. Here 70 × 30 stays 2100 ml because the factor is 30. Hydration in glasses divides those millilitres by 250.
With a US header, weight is pounds and field b is ml per lb. The 2100 ml and 2640 ml examples are from kilograms and ml/kg. Format.volume can print litres at 2100 ml; extras keep 2100 ml after rounding.
Enter weight, enter ml per kg, then Calculate. Zero in a field leaves a blank. A comma in 30.5 parses. A fluid estimate, not a clinic order.
70 kg × 30 give 2100 ml. 80 × 33 give 2640 ml. 60 × 35 give 2100 ml. Two different inputs can land on the same 2100 ml.
ml = kg × ml/kg
ml = kg × ml/kg. 70 and 30 give 2100 ml. 60 and 35 again give 2100 ml.
2100 ml
2640 ml
2100 ml
Related calculators
Common questions
How many ml at 70 kg and 30 ml/kg?
2100 ml. 70 × 30, then rounding and an ml suffix.
What about 80 kg and 33?
2640 ml. 80 × 33 = 2640.
What about 60 kg and 35?
2100 ml. Another pair, the same 2100.
Does the calculator add training?
No. The product only. 350 ml for a session lives on hydration during exercise.
How is this different from the water page?
There a fixed 33 and an add-on. Here you enter ml/kg. 70 × 30 is 2100, not 2310.
Is 2100 ml an order?
No. A estimate from a product. Not a clinic verdict.
What if weight is 0?
A blank. Mass and the factor must be positive.
Does a comma in 30.5 work?
Yes. 70 × 30.5 gives 2135 ml.
Does a US header change 70 × 30?
Yes. Then 70 is pounds and 30 is ml/lb. The 2100 ml examples are metric.
How do I calculate water from weight and ml/kg?
ml = kg × ml/kg. At 70 and 30: 2100 ml. At 80 and 33: 2640 ml. At 60 and 35: again 2100 ml — different pair, same total.
How does this differ from the daily water calculator?
That page uses about 33 ml/kg plus an optional training add-on. Here you enter your own coefficient and no training bump is added.
Is 2100 ml a clinic order?
No. It is the product of the numbers you enter. Kidney or heart disease and an individual plan belong with a clinician.
Does the result show glasses?
No. This page stays in millilitres. Conversion to glasses lives on the water-habits page (about 250 ml per glass).
Knowledge sources
The result is ml = kg × ml/kg. You enter the factor.
Page updated in 2026.