Use our free pet calculator to instantly find your pet’s age in human years, daily calorie needs, healthy weight range, and food portions — works for dogs, cats, rabbits, hamsters, and birds.
What Is a Pet Calculator?
A pet calculator is an online tool that helps pet owners make informed decisions about their pet’s health, nutrition, and care. Instead of guessing how much to feed your cat or wondering how old your rabbit is in human years, a pet calculator gives you a clear, personalised answer in seconds.
Whether you have a dog, cat, rabbit, hamster, or bird, the right numbers can help you give your pet a longer, healthier life.
Pet Age Calculator: How Old Is Your Pet in Human Years?
Different pets age at very different rates. Here’s a quick reference for common pets:
| Pet Type | 1 Pet Year = | Average Lifespan |
|---|---|---|
| Small dog (under 20 lb) | ~15 human years (year 1) | 12–16 years |
| Large dog (over 50 lb) | ~12 human years (year 1) | 8–12 years |
| Cat | ~15 human years (year 1) | 12–18 years |
| Rabbit | ~12 human years (year 1) | 8–12 years |
| Hamster | ~26 human years (year 1) | 2–3 years |
| Parrot (small) | ~5 human years | 15–30 years |
How to calculate your pet’s age in human years: For dogs, use the formula based on breed size. For cats, the first 2 years count as roughly 25 human years, then add 4 years per calendar year after that.
Pet Calorie Calculator: How Many Calories Does My Pet Need?
Daily calorie needs vary by species, weight, age, and activity level. Here are general daily calorie (kcal) guidelines:
| Pet | Weight | Daily kcal (maintenance) |
|---|---|---|
| Dog | 10 lb (4.5 kg) | ~295 kcal |
| Dog | 30 lb (13.6 kg) | ~674 kcal |
| Dog | 60 lb (27 kg) | ~1,112 kcal |
| Cat | 8 lb (3.6 kg) | ~200–250 kcal |
| Cat | 10 lb (4.5 kg) | ~240–300 kcal |
| Rabbit | 4.4 lb (2 kg) | ~100–120 kcal |
The standard formula for a pet’s Resting Energy Requirement (RER) is: RER = 70 × (body weight in kg)^0.75. Multiply by an activity factor (1.2–1.8) to get the daily maintenance energy requirement (MER).
Pet Weight Calculator: Is My Pet a Healthy Weight?
Healthy weight ranges differ widely by species and breed. A general guide:
- Dogs: You should be able to feel (but not see) your dog’s ribs. If ribs are visible, your dog is underweight. If you can’t feel them at all, your dog is overweight.
- Cats: Ideal weight for most domestic cats is 8–10 lb (3.6–4.5 kg). Cats over 12 lb (5.4 kg) are generally considered overweight.
- Rabbits: Healthy weight depends on breed — a Netherland Dwarf should weigh around 2 lb, while a Flemish Giant can be 13–15 lb.
Use your vet’s Body Condition Score (BCS) chart — a 9-point scale — to assess your pet’s weight accurately.
Pet Food Calculator: How Much Should I Feed My Pet Per Day?
Feeding amounts depend on your pet’s weight, life stage, and the calorie density of the food you’re using. Here’s a quick guide:
| Pet | Weight | Dry Food per Day (approx.) |
|---|---|---|
| Dog | 10 lb | ¾ – 1 cup |
| Dog | 30 lb | 1¾ – 2¼ cups |
| Dog | 60 lb | 3 – 3¾ cups |
| Cat | 8–10 lb | ¼ – ⅓ cup dry food |
| Rabbit | 4–6 lb | ¼ cup pellets + unlimited hay |
Always check the feeding guide on your specific pet food packaging, as calorie density varies significantly between brands and formulas.
Pet Calculator by Type: Quick Links
Looking for a calculator for a specific pet or topic? Use these direct links:
- Dog Calorie Calculator by Breed
- Dog Food Calculator by Weight
- Dog Age Calculator by Breed
- Dog Ideal Weight Calculator
- Dog Nutrition Calculator
- Pet Age Calculator (Dogs, Cats, Rabbits & More)
Frequently Asked Questions
What is the best pet calculator online?
The best pet calculator depends on what you need. For dogs, PetSmush offers free calculators for calories, food portions, age conversion, weight, and medication dosing. For general multi-species needs, look for calculators that cover dogs, cats, rabbits, and small animals.
How do I calculate my pet’s age?
Pet age calculation depends on the species. Dogs: use a size-adjusted formula — small dogs age slower than large dogs after the first two years. Cats: the first year equals ~15 human years, the second year equals ~9 more, then roughly 4 human years per calendar year after that. Rabbits age approximately 12 human years in their first year.
How many calories does my pet need per day?
Use the RER formula: 70 × (body weight in kg)^0.75. Then multiply by your pet’s life stage factor — 1.2 for a neutered adult, 1.4 for an intact adult, 1.6–2.0 for puppies and kittens, and 1.1 for weight loss. Your vet can confirm the right target for your individual pet.
Is there a pet calculator app?
Yes. Several apps offer pet calculators including PetCoach, Petcube, and general vet apps. However, free web-based calculators on sites like PetSmush often give more detailed, customised results without requiring a download.
Can I use a dog calculator for cats?
No — dogs and cats have different calorie needs, aging patterns, and healthy weight ranges. Always use a species-specific calculator for accurate results. Using a dog calculator for a cat can significantly over- or under-estimate food portions.