US-unit formula guide
Water Per Pound Formula
Quick answer
Use this page for the US-unit formula, not the metric shortcut. A practical rule is 0.5–0.75 oz per pound of body weight per day. For a 180 lb adult, that is about 90–135 oz or 2.7–4.0 L. Use the lower end for quiet, cool days and the higher end for exercise, heat, or heavy sweating.
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Your daily goal: 101 ounces, 12 glasses.
Your daily goal
Updates instantlyof water a day · about 12 glasses or 6 half-litre bottles
Typical range: 90-135 fl oz. Use it as a flexible target, not a medical limit.
Start
2 glasses
7:00 AM
Taper
9:00 PM
for better sleep.
Food fluid
+0.7 L
typical food water
- 3.0
- Litres
- 101
- Ounces
- 12
- Glasses
Why this number
We start from a weight-based range, then adjust the point estimate for activity, climate, life stage, and GLP-1 settings. Food water is shown separately so the drink goal stays actionable.
Full methodologyNext step
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.
Daily goal
101 fl oz
The link and preview image include your weight and settings.
Per-pound water chart
| Body weight | Low end | High end | Litres range |
|---|---|---|---|
| 120 lb | 60 oz | 90 oz | 1.8–2.7 L |
| 150 lb | 75 oz | 113 oz | 2.2–3.3 L |
| 180 lb | 90 oz | 135 oz | 2.7–4.0 L |
| 210 lb | 105 oz | 158 oz | 3.1–4.7 L |
| 240 lb | 120 oz | 180 oz | 3.5–5.3 L |
Why it is a range
Body weight is a useful anchor, but it is not the whole story. The same person needs more water after training, in heat, during illness, or when eating less water-rich food. Treat the range as a starting point and adjust from there.
Frequently asked
How much water per pound of body weight should I drink?
A useful rule of thumb is 0.5–0.75 fluid ounces per pound of body weight per day. Use the lower end for sedentary, cool days and the higher end for activity, heat, or heavy sweating.
Is one ounce per pound too much?
For many people, one ounce per pound is more than needed. It can be reasonable for some large, active, sweaty people, but most adults fit better around 0.5–0.75 oz per pound.
Does the per-pound rule include food water?
For this site, the per-pound rule is treated as a drinking-water target. Food water is shown separately as context because it varies by diet.
Sources
- 1.U.S. National Academies (IOM/NAM), 2005 — Adequate total water intake of about 3.7 L/day for men and 2.7 L/day for women, including water from food and all beverages.
- 2.European Food Safety Authority (EFSA), 2010 — Adequate total water intake of 2.5 L/day for men and 2.0 L/day for women under temperate conditions.
- 3.Mayo Clinic — General guidance of roughly 2.7–3.7 L of total fluids a day, with thirst and pale-yellow urine as everyday checks.