Horse Daily Water Intake Calculator
Calculate how much water your horse needs daily based on weight, activity level, temperature, and feed type.
How Horse Daily Water Intake Is Calculated
Water is the most critical nutrient for horses. A horse can survive weeks without food but only days without water. Dehydration is a leading trigger for colic, the number one cause of death in domestic horses.
Base Water Requirement
Base_Liters = Body_Weight_kg × 0.05
A horse at rest in a temperate climate needs approximately 5 liters of water per 100 kg of body weight per day. For a typical 500 kg horse, that is 25 liters (about 6.6 US gallons) at minimum.
Activity Adjustment
Exercise increases water needs through sweat loss. Horses are heavy sweaters — they can lose 10-15 liters per hour during intense exercise.
| Activity Level | Multiplier |
|---|---|
| Rest / light turnout | 1.0× |
| Light work (trail riding, walking) | 1.25× |
| Moderate work (schooling, trotting) | 1.5× |
| Heavy work (jumping, galloping) | 2.0× |
| Intense work (racing, endurance) | 2.5× |
Temperature Adjustment
| Temperature Range | Multiplier |
|---|---|
| Below 5°C (41°F) | 0.8× |
| 5-15°C (41-59°F) | 1.0× |
| 15-25°C (59-77°F) | 1.2× |
| 25-35°C (77-95°F) | 1.5× |
| Above 35°C (95°F) | 1.8× |
Feed Type Adjustment
Horses on dry hay need significantly more water than those on fresh pasture because pasture grass contains 60-80% water by weight.
- Dry hay or grain diet: 1.3× multiplier
- Mixed hay and pasture: 1.0× multiplier
- Primarily fresh pasture: 0.8× multiplier
Final Formula
Daily_Water = Base_Liters × Activity_Mult × Temp_Mult × Feed_Mult
Worked Example
A 550 kg horse doing moderate work in 28°C weather, eating dry hay:
- Base: 550 × 0.05 = 27.5 L
- Activity: 27.5 × 1.5 = 41.25 L
- Temperature: 41.25 × 1.5 = 61.9 L
- Feed: 61.9 × 1.3 = 80.4 L (approximately 21 US gallons)
Lactating Mares
Lactating mares need an additional 50-75% more water above their calculated amount. A mare producing milk may drink over 75 liters per day in warm weather.