Overview
Rather than asking “am I hydrated?”, this tool compares fluid intake with an estimated target. The percentage supports daily tracking, but it does not measure body fluid status and does not replace medical assessment when dehydration is suspected.
Formula
Lower and upper targets are calculated from weight, climate and activity, then intake is divided by the target midpoint and multiplied by 100.
How it works
Enter weight and activity
Use the same day's activity where possible.
Choose weather
Heat and humidity increase needs.
Enter fluids
Add water and drinks, and remember food also contributes.
Worked examples
70 kg, no exercise, temperate, 2 L drunk
The target is about 2.1–2.45 L with a 2.28 L midpoint, so coverage is about 88%.
Same conditions with 2.5 L
Coverage exceeds 100%, which does not automatically mean better hydration.
Frequently asked questions
Does 100% mean perfect hydration?
No. The target is an estimate, and the percentage does not measure fluid or electrolyte balance.
Should I drink until 100%?
Do not force it. Drink according to thirst and conditions, and avoid large amounts quickly.
Is urine color enough?
It is a simple practical cue, not a diagnosis. Some vitamins and medications change color.
Is it suitable for kidney patients?
It should not be used as their target; a clinician sets the appropriate fluid amount.
This calculator is for educational and informational purposes only and is not a substitute for professional advice.