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Hydration range Health-adjacent estimate

Dog & Cat Water Intake Calculator

A healthy dog needs roughly 50–60 ml of water per kilogram of body weight a day, and a cat about 40–50 ml — food moisture included. Enter your pet’s weight and we’ll turn that into a daily target in cups, fluid ounces, and millilitres, so you know what normal looks like.

Pet

Typical water per day

— cups / day

How to use it

  1. 1 Pick dog or cat and enter your pet’s weight.
  2. 2 Read the daily water range and the typical mid-point in cups and ounces.
  3. 3 Watch for big changes — a sudden jump or drop in drinking is worth a vet call.

Why this matters

Both too little and too much drinking can be early signs of a problem — kidney disease, diabetes, and urinary issues all show up first as a change in thirst, especially in cats. Knowing your pet’s normal daily range makes it far easier to notice when something shifts. The estimate uses the standard veterinary rule of about 50–60 ml/kg/day for dogs and 40–50 ml/kg/day for cats.

Dog water intake

For a healthy adult dog, a practical daily starting point is about 50–60 ml of total water per kilogram of body weight. That includes water in food, so a dog eating wet food may drink less from the bowl than a dog eating dry kibble.

Use the calculator to get a baseline, then watch for changes. Heat, exercise, lactation, salty treats, vomiting, diarrhea, and some medications can all move the number; a sudden jump or drop is a reason to check in with your veterinarian.

Cat water intake

For cats, the estimate is about 40–50 ml of total water per kilogram of body weight per day. Cats often get a large share of their water from food, so a cat on canned or pouch food may look like a light bowl-drinker and still be normal.

What matters most is the pattern. A cat that suddenly drinks or urinates more, especially an older cat, should be checked for issues such as kidney disease, diabetes, or hyperthyroidism rather than just written off as being thirsty.

Frequently asked questions

How much water should my dog drink a day?

About 50–60 ml per kg of body weight per day, so a 20 kg dog needs roughly 1–1.2 litres (about 4.5–5 cups). Active dogs and hot weather push it higher. Counting both bowl water and moisture in food.

How much water should a cat drink?

Around 40–50 ml per kg per day — about 180–225 ml (¾–1 cup) for a typical 4.5 kg cat. Cats on wet food drink much less from the bowl because their food is ~75% water, which is completely normal.

When is changed drinking a problem?

Drinking a lot more or a lot less than usual — or producing much more urine — can signal kidney disease, diabetes, or a urinary problem. Increased thirst in an older cat especially is worth a vet visit. Use this tool to learn your pet’s baseline so you can spot the change.

Keep going

Dog & Cat Feeding Calculator Daily calories and cups, from the vet-standard RER/MER formula. Dog & Cat Ideal Weight Checker Estimate ideal weight from the vet’s 9-point body condition score. Dog & Cat Age Calculator Pet years to human years — the real curve, not the ×7 myth.