Daily Water Intake Calculator

What it is

This calculator turns the Korean adequate water intake for your sex and age group into a daily target in mL. It then adds extra for the exercise you do and for hot weather, using numbers you can edit, and shows how many cups of your usual size that makes. A checklist lets you tick off each cup during the day. The form opens with an example (male 30 to 49, 30 minutes of exercise, 20°C, a 200 mL cup) so you see a result at once. Amounts are in mL and weight in kg, and everything is computed in your browser.

How to use

1. Choose your sex and age group.
2. Enter your daily exercise time in minutes and the outside temperature in °C.
3. Review the extra per 30 minutes, the heat threshold and the heat percentage. They are examples, so change them to suit you.
4. Enter the size of your usual cup or bottle in mL.
5. Optionally enter your weight to see a reference amount from the per-kg rule.
6. Read the total, the cups and the math lines, and tick cups as you drink them.

How it works

• The base is adequate intake of drinks from the 2025 Korean Dietary Reference Intakes summary (Ministry of Health and Welfare and the Korean Nutrition Society, 2025-12). Men 30 to 49 have 1,200 mL and women 30 to 49 have 1,000 mL.
• Exercise extra = exercise minutes / 30 x extra per 30 minutes. For 60 minutes at 350 mL that is 700 mL.
• Heat extra applies when the temperature is at or above your threshold. It is the base drink amount times your percentage. The 30°C threshold and 10% are examples.
• The exercise and heat extras and the 30 mL per kg rule are not sourced standards, which is why you can edit them.
• The total is computed first and rounded to a whole mL once. Cups are that total divided by cup size, rounded up.
• Limits: weight 30 to 300 kg, exercise 0 to 600 minutes, temperature -30 to 50°C, cup 50 to 1,000 mL.
• Pregnancy, breastfeeding and ages under 19 are not covered. Retrieved 2026-10-04.

Examples

Male 30 to 49, 60 minutes of exercise at 350 mL per 30 minutes, 20°C, 200 mL cup.

Item	Math	Result
Base adequate intake (drinks)	table value	1,200 mL
Exercise extra	60 / 30 x 350	700 mL
Heat extra	20°C is below 30°C	0 mL
Total	1,200 + 700	1,900 mL
Cups	1,900 / 200 = 9.5	10 cups

The adequate total water including food for the same person is 2,500 mL, shown separately.

Good to know

This is a rough estimate for reference. It does not diagnose or treat anything, and a doctor should guide you if you are worried about your health. If a kidney or heart condition limits your fluids, follow your doctor’s instructions. Soup, fruit and other food contain water too, so drinks alone are not meant to cover everything. Thirst and urine color are useful signals as well.