Water Intake Calculator
Enter your body weight, daily exercise, and climate, and this calculator estimates how much water you should drink per day — shown in liters, US fluid ounces, and 8-oz glasses. It uses the widely used per-kilogram baseline plus standard add-ons for exercise and hot weather. It runs entirely in your browser: free, instant, and no sign-up.
Enter your weight to see your estimated daily water intake in liters, ounces, and glasses.
Frequently asked questions
A widely used baseline is about 30–35 ml per kilogram of body weight per day (roughly half an ounce to two-thirds of an ounce per pound) — around 2.3 L for a 70 kg (154 lb) adult. Add roughly 350 ml (12 oz) per 30 minutes of exercise, and more in hot weather. This calculator applies those rules to your numbers.
No — it's an estimate from general guidelines, not medical advice. Real needs vary with health conditions, pregnancy or breastfeeding, medications, altitude, and diet (food typically covers about 20% of fluid intake). Thirst and pale-yellow urine are good practical checks; ask a doctor about your specific needs.
Yes — all beverages count toward fluid intake, including caffeinated ones (the diuretic effect of normal coffee consumption is small), and food typically contributes around 20% on top. The target shown here is for fluids you drink.
Yes — free, no sign-up, and everything is calculated in your browser, so your weight and details are never uploaded or stored anywhere.
More free tools
Percentage Calculator
Find a percentage of a number, or what % one number is of another.
Try toolDiscount Calculator
See the sale price and how much you save on any discount.
Try toolTip Calculator
Work out the tip, total, and per-person amount on any bill.
Try toolLoan Calculator
Estimate the monthly payment, total interest, and cost of a loan.
Try toolAge Calculator
Find your exact age in years, months, and days from a birth date.
Try toolBMI Calculator
Find your BMI and weight category from height and weight.
Try toolReady to take control of your subscriptions?
Track every subscription, catch renewals before they hit, and stop paying for what you don't use — no bank connection required.
- No bank connection required
- No credit card to start
- Works in any country & currency
- Reminders before every charge
- One-time pricing, no recurring fee
- 30-day money-back guarantee