How Much Water Should You Really Drink?
Published Apr 13, 2026 · 6 min read
The "8 glasses a day" rule has no scientific basis. Your actual water needs depend on your weight, activity level, climate, and diet.
A Better Formula
Daily water (oz) = Body weight (lbs) Γ 0.5 to 0.67
Add 12 oz for every 30 minutes of exercise.
Add 12 oz for every 30 minutes of exercise.
A 160 lb person needs roughly 80-107 oz (2.4-3.2 liters) per day. Active people in hot climates lean toward the higher end.
Signs You're Not Drinking Enough
- Urine is dark yellow (should be pale straw)
- Headaches, especially in the afternoon
- Fatigue and difficulty concentrating
- Dry mouth and lips
- Less than 4 bathroom trips per day
Tips for Drinking More
- Keep a water bottle within arm's reach at all times
- Drink one glass before each meal
- Set hourly reminders on your phone
- Count herbal tea, fruits, and soups toward your goal
Try it: Use our Water Intake Calculator to get a personalized daily hydration target.