Per pound
Water Intake for 180 lb
Quick answer
A 180 lb (82 kg) adult should drink about 3 litres (101 fl oz, or 12 glasses) of water a day at a moderate activity level in a temperate climate. Needs range from roughly 2.6 litres on a quiet, cool day to about 3.6 litres when active or in heat — add more for exercise, pregnancy, and illness.
Fine-tune
Your daily goal: 101 ounces, 12 glasses.
Your daily goal
of water a day · about 12 glasses or 6 half-litre bottles
- 3.0
- Litres
- 101
- Ounces
- 12
- Glasses
Your sip schedule
- 7:00 AM · Start the day2 glasses
- 9:48 AM · Top up2 glasses
- 12:36 PM · Top up2 glasses
- 3:24 PM · Top up2 glasses
- 6:12 PM · Top up2 glasses
- 9:00 PM · Wind down2 glasses
Ease off after 9:00 PM for better sleep.
Electrolytes? Skip them today
For everyday hydration, plain water and a normal diet cover your electrolytes just fine.
A friendly estimate for healthy adults, not medical advice. Your needs rise with heat, exercise, illness, pregnancy, and some medications. Don't drink more than ~1 litre per hour.
How much water is that? A 180 lb breakdown
For a 180 lb (82 kg) adult, the daily drinking goal lands near 3 litres (101 fl oz) at a moderate activity level. That's about 12 glasses or 6 half-litre bottles. On a quiet, cool day you might need as little as 2.6 litres; on an active day in the heat, closer to 3.6 litres.
| Body weight | Litres | Ounces | Glasses |
|---|---|---|---|
| 180 lb | 3 | 101 | 12 |
| 170 lb | 2.8 | 96 | 11.5 |
| 190 lb | 3.1 | 106 | 12.5 |
| 160 lb | 2.7 | 91 | 11 |
| 200 lb | 3.3 | 111 | 13 |
Where the 180 lb number comes from
The baseline is roughly 0.5–0.75 ounces of water per pound of body weight, the widely cited rule of thumb backed by the U.S. National Academies and EFSA. A 180 lb person therefore lands near 3 litres before we layer on activity and climate.
The number above assumes a moderately active day in a temperate climate. Add about 350 ml (12 oz) for every half-hour of exercise, and around 10% more in hot or humid weather. Pregnancy, breastfeeding, fever, and some medications push it higher still. The calculator above adjusts all of this live — try it.
Don't drink it all at once
Your kidneys can clear only about 1 litre of water per hour. Spreading the goal across the day — and easing off in the last two hours before bed — keeps you comfortable and avoids nighttime bathroom trips. Pale yellow urine is a good everyday check that you're in the right zone.
Make it exact for 180 lb
Add your real activity, climate, and life stage to dial in a goal made for you — not just your weight.
Frequently asked
How much water should a 180 lb person drink a day?
A 180 lb (82 kg) adult should drink about 3 litres (101 fl oz) of water a day at a moderate activity level — roughly 12 glasses or 6 half-litre bottles. That ranges from around 2.6 litres on a quiet, cool day up to about 3.6 litres when you exercise or it's hot.
How many ounces of water is that for 180 lb?
For a 180 lb adult, a moderate day is about 101 fluid ounces (3 litres). On a light day you might manage with 87 oz; on an active or hot day you can need 123 oz or more.
Is "half your body weight in ounces" right for 180 lb?
Half your body weight in ounces is 90 oz, a sound floor for a 180 lb adult who sits most of the day. If you're active, pregnant, or in the heat, aim higher — toward 101 oz or more.