How Much Water Should You Actually Drink Every Day?

The "8 glasses a day" rule gets repeated so often that it's basically become fact in most people's minds, but it's really just a rough average that doesn't account for body size, activity level, or climate. Here's a more useful way to think about it.

A Better Starting Point

A commonly used guideline is around 30-35ml of water per kilogram of body weight. So someone weighing 70kg would land somewhere around 2.1-2.4 liters a day as a baseline, before accounting for exercise or heat.

Why Activity Level Changes the Number

If you're training regularly or sweating a lot through the day, you'll need more than the baseline to replace what you're losing. On heavy training days, adding an extra 500ml-1 liter isn't unusual.

You're Also Getting Water From Food

Water intake isn't just about what you drink. Fruits, vegetables, and soups all contribute meaningfully to your daily total, which is part of why exact numbers vary so much between guidelines.

Signs You're Not Drinking Enough

• Dark yellow urine (pale yellow is generally a good sign you're well hydrated)
• Feeling unusually tired or getting headaches for no clear reason
• Dry mouth or unusually strong thirst throughout the day

Can You Drink Too Much?

Yes, though it's uncommon in normal daily life. Drinking extremely large amounts of water in a short period can dilute your body's sodium levels. This mostly comes up in extreme situations like endurance events, not regular day-to-day hydration.

The Simple Takeaway

Don't stress over hitting an exact number every single day. Use your body weight as a rough guide, drink more on hot or active days, and pay attention to your urine color as a simple, practical check.