How much water should my dog (or cat) drink per day?
Enter your pet's weight, species, and the percentage of wet food in their diet to estimate the recommended daily water range, in milliliters and in cups.
Recommended water per day
500–600 ml/day
That's approximately 2.1 to 2.5 cups (240 ml) per day.
Since the diet is mostly dry, virtually all of this amount should come from the water bowl (dry food has very little water). This value does not account for extra losses from heat, exercise, fever, or illness.
How the calculation works
Maintenance water needs are usually expressed in milliliters per kilogram of body weight per day (ml/kg/day). Under normal conditions in a thermoneutral environment, dogs typically need about 50 to 60 ml/kg/day, while cats need a slightly lower range of 40 to 50 ml/kg/day — reflecting the naturally weaker thirst instinct in cats.
This maintenance range accounts for all the water a pet gets throughout the day, whether from drinking at the bowl or from moisture in their food. Dry food contains little water (about 6% to 10%), so nearly the entire requirement has to come from the water bowl. Wet food (pouches, cans), on the other hand, typically contains 70% to 80% water, supplying a good part of daily hydration directly through food.
That's why, when you indicate a higher percentage of wet food in the diet, the calculator proportionally lowers the recommended range of "extra" water — down to a maximum reduction of 50% for a 100% wet diet. This is a simplified, educational estimate, not a clinical fluid therapy calculation (which requires individual veterinary assessment, especially in cases of dehydration, vomiting, diarrhea, or kidney disease).
Factors like heat, ambient humidity, physical exercise, pregnancy, nursing, fever, and certain illnesses (diabetes, kidney disease) increase actual water needs above the maintenance range — in those cases, offer water freely and watch for signs of dehydration or excessive thirst.
Frequently asked questions
What are the signs of dehydration in dogs and cats?
The most common signs include dry or tacky gums (instead of moist and pink), lethargy, loss of appetite, sunken eyes, and reduced skin elasticity: when you gently lift the skin between the shoulder blades (the skin tent test), it should snap back into place quickly — if it takes a while to "unwrinkle" or stays tented, that's a sign of dehydration and the pet should be seen by a veterinarian as soon as possible.
Why do cats naturally drink so little water?
Domestic cats descend from ancestors in arid regions who got most of their hydration from prey (which can be 70-75% water). Because of this, cats keep a weaker thirst instinct than dogs, even when fed dry food — which is why it's so important to always offer fresh water nearby and consider wet food in the diet.
Does wet food hydrate more than dry food?
Yes. Wet food (pouches, cans) is usually 70% to 80% water, compared to only 6% to 10% in dry kibble. Pets fed mostly wet food tend to drink less water from the bowl because they already get a good part of their hydration from the food — that's why our calculator lowers the recommended range of extra water as you increase the wet-food percentage.
Do hot weather or exercise increase water needs?
Yes, significantly. Heat, high humidity, physical exercise, fever, pregnancy, nursing, and certain illnesses (like diabetes and kidney disease) increase fluid loss and, as a result, a pet's water needs — this calculator's range is a maintenance estimate under normal conditions and may need to be higher in those scenarios.
My pet is drinking a lot more water than usual, should I be worried?
Yes. A noticeable, sustained increase in thirst (polydipsia) can be an early sign of conditions like diabetes, kidney disease, liver disease, or hormonal disorders. If your pet's water intake has clearly changed for more (or much less) without an obvious explanation like heat or a diet change, schedule a veterinary visit.
Important notice
This calculator is for educational purposes and does not replace a veterinary evaluation. When in doubt, consult a veterinarian.Sources
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