Estimate daily water intake from weight, activity level and climate with liters and glasses per day shown clearly. Your data never leaves your device.
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Quick answer: Water Intake Calculator — Daily water needs Free, no signup, runs in your browser. See below for the interactive tool, 4-step guide and FAQs.
Enter weight to calculate
Base = weightKg × 35 mlDeep dives from the Tool4SaaS blog — tested workflows, print sizes and fixes.
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Target starts at weight times 35 milliliters and 500 milliliters if active or hot. Seventy kilograms times 35 equals 2450 milliliters and 500 for drills gives 2950 milliliters or twelve cups. Sums run on-device with net off and no file sent. See /terms for context.
General hydration information only, never prescription for renal or cardiac disease. Kidneys, heart failure, pregnancy, and diuretics change needs sharply. Seventy kilograms needs about 2.45 liters normally, but swelling or illness needs clinician input. Consult healthcare professional for personal guidance and see /terms.
Seventy-kilogram lightly active adult in temperate weather needs about 2.45 liters or ten glasses, spread morning to evening. Adding 500 milliliters per hard workout or hot day reaches 2.95 liters or twelve glasses. Sipping steadily and front-loading mornings avoids nocturia. Track for a week and see /terms.
Caffeine exerts mild diuretic effect while sodium retains water, creating offsetting influences. Two large coffees may add 300 milliliters requirement, while salty ramen adds thirst without true deficit. Monitoring pale-yellow urine across three days reveals net balance better than rigid cup counting. Adjusting 250 milliliters increments fine-tunes comfort.
Prolonged sweating beyond ninety minutes depletes sodium and potassium that plain water cannot replace. Seventy-kilogram runner losing one liter hourly needs 500 to 700 milligrams sodium per hour and fluid. Cramping, dizziness, or confusion signals medical urgency. Consulting sports clinician and testing sweat rate personalizes strategy.
Daily target starts at weight times 35 milliliters and 500 milliliters if active or in hot climate, with glasses as milliliters divided by 250. Seventy kilograms times 35 equals 2450 milliliters and 500 for training gives 2950 milliliters or about twelve glasses. Fifty-five-kilogram office worker needs about 1925 milliliters or eight glasses. Hydration table benchmarks weights comprehensively | Weight | Temperate base | Active-hot total | 55 kilograms | 1925 milliliters, 8 glasses | 2425 milliliters, 10 glasses | 70 kilograms | 2450 milliliters, 10 glasses | 2950 milliliters, 12 glasses | 90 kilograms | 3150 milliliters, 13 glasses | 3650 milliliters, 15 glasses. Edge case of kidney disease requires restriction, not average. Limitation ignores food moisture content. Spread intake morning to evening for steady balance. This is general information only, not medical advice. See /terms.
Enter weight thirty to two hundred kilograms, pick activity tier, and tick hot climate if sweating heavily. Model adds flat 500 milliliters for active or hot, so seventy-kilogram sedentary temperate is 2450 while active-hot is 2950. Coffee, salty meals, high protein, and endurance sessions shift needs daily by 250 to 750 milliliters. Second example at eighty-five kilograms active-hot reaches 3475 milliliters or fourteen glasses. Adjustment table shows drivers clearly | Factor | Increment added | Example outcome | Hard hour training | and 500 milliliters | 2950 to 3450 total | Hot humid climate | and 500 milliliters | 2450 to 2950 total | High sodium meal | and 250 thirst | temporary increase. Edge case of heart failure and pregnancy fluid caps need clinician rules. Limitation omits humidity precision. This is general information only, not medical advice. See /terms.
Take seventy kilograms lightly active with 2450 milliliters base or ten glasses, rising to 2950 milliliters or twelve glasses when hot or training with activity flag. Add 500 milliliters per hard hour, sip 250 to 500 per waking hour, and watch pale-yellow urine as gauge for adequacy. Test fifty-five kilograms for 1925 base versus ninety kilograms for 3150 to scale intuition across body sizes. Verify eighty-five kilograms active-hot at 3475 milliliters for extended coverage. Edge case of hyponatremia from overdrinking beyond thirst during marathons requires electrolyte planning with sodium. Limitation covers averages only, excluding illness, diuretics, and altitude diuresis effects. This is general information only, not medical advice, so see /terms and ask clinician. For calorie balance try tracker at /calorie-calculator free offline with private math.