How to Read This Chart
The figures below are baseline estimates for a sedentary-to-lightly-active person in a mild climate. They're a fast starting reference, not a substitute for a personalised number — activity level and climate can shift the actual figure by a litre or more in either direction.
Water Intake Chart by Age (Adults)
| Age Group | Typical Daily Water (Men) | Typical Daily Water (Women) |
|---|---|---|
| 19–30 years | 2.5–3.0 L | 2.0–2.5 L |
| 31–50 years | 2.5–3.0 L | 2.0–2.5 L |
| 51–70 years | 2.3–2.8 L | 1.8–2.3 L |
| 70+ years | 2.0–2.5 L | 1.7–2.1 L |
Fluid needs decline slightly with age partly because muscle mass (which holds more water than fat) tends to decrease, and overall body size and activity often reduce as well. Older adults should still watch intake carefully, though, since thirst sensation also declines with age — see our signs of dehydration guide.
Water Intake Chart by Body Weight (Adults)
| Body Weight | Baseline Target (33 ml/kg) |
|---|---|
| 50 kg (110 lb) | 1.65 L |
| 60 kg (132 lb) | 2.0 L |
| 70 kg (154 lb) | 2.3 L |
| 80 kg (176 lb) | 2.6 L |
| 90 kg (198 lb) | 3.0 L |
| 100 kg (220 lb) | 3.3 L |
This weight-based table reflects only the base calculation (33 ml per kg) with no activity or climate adjustment — add several hundred ml for regular exercise, and more again for a hot climate.
Water Intake for Children
Note: children's fluid needs are typically calculated using different clinical methods (such as the Holliday-Segar formula) rather than the adult weight-based guideline, and should ideally be guided by a pediatrician rather than a general chart.
| Age Group | Typical Daily Total Fluid |
|---|---|
| 4–8 years | ≈1.2 L |
| 9–13 years | ≈1.6–1.8 L |
| 14–18 years | ≈1.8–2.6 L |
See our Holliday-Segar formula guide for the clinical weight-tiered method commonly referenced in pediatric contexts.
Why a Chart Isn't Always Enough
Charts are fast, but they average across a wide range of people. Two 70 kg adults — one sedentary in a cool office, one training daily in a hot climate — can have genuinely different fluid needs despite an identical weight-based starting point. For a number tailored to your specific activity and climate, use the calculator below rather than relying on the chart alone.