Pet Age Calculator: Find Your Pet’s Human Age (Dog & Cat)

What This Tool Is For

This tool will assist you in determining how your pet is doing in their life; being aware of the human age equivalency for your pet will help you to:

• Make better decisions about their vet care as senior pets require more specialized care than young dogs.
• Set realistic expectations – the 10 year old large dog is considerably older than the 10 year old small dog.
• Understand behaviour changes, such as changes in movement speed or new habits, which often have an age related connection.
• Share with other people by copying or saving the result in image format for easy sharing.

When you adopt your pet you may not know all of the information regarding their history so the use of this tool is great.

How It Works

Input the pet type, size (for dogs), and number of years/months of age. You will receive an immediate calculation of:

• Your pets human equivalent and life stage.

In the case of a cat, size does not impact how fast they age in the same way a dog does. The calculation will be the same for all cats.

In contrast to cats, size impacts the rate at which dogs age after their second birthday. A large dog will mature quicker than a small one.

The life stages for cats are:

• Kitten: under 1 year
• Junior: 1 to 2 years
• Adult: 3 to 10 years
• Senior: 11 to 14 years
• Geriatric: 15 years and older

The life stages for dogs are:

• Puppy: under 1 year
• Junior: 1 year
• Adult : 2 to 6 years
• Mature: 7 to 9 years
• Senior: 10 years and older

The Formula Behind the Calculator

The Calculator is built based on American Veterinary Medical Association (AVMA) guidelines. It will not use the old “Times 7” method to calculate your pets age.

Variable(s) that are used:

• y = Years of age (Complete)
• m = Months left (0-11)
• f = Size Factor (for dogs only)

If the pet is under 1 year old

$$\text{Human Age} = \frac{m}{12} \times 15$$

If the pet is exactly 1 year old

$$\text{Human Age} = 15 + \frac{m}{12} \times 9$$

If the pet is 2 years or older

$$\text{Human Age} = 24 + (y – 2) \times f + \frac{m}{12} \times f$$

• For cats, f = 4 always
• For dogs, f depends on breed size:

Step-by-Step Example

A 5-year-old large dog

y = 5, m = 0, f = 6

$$\text{Human Age} = 24 + (5 – 2) \times 6 + \frac{0}{12} \times 6$$ $$= 24 + 3 \times 6 + 0$$ $$= 24 + 18 = 42 \text{ human years}$$

A 3-year-old cat with 6 months

y = 3, m = 6, f = 4

$$\text{Human Age} = 24 + (3 – 2) \times 4 + \frac{6}{12} \times 4$$ $$= 24 + 4 + 2 = 30 \text{ human years}$$

Limitations and Disclaimer

This estimate will be broad and not used medically.

• Breeds of varying sizes are not taken into consideration when calculating estimates.
• 10-Lb Chihuahua versus 20-Lb Beagle: They are both “small”, but will likely have different life cycles.
• Each individual’s health history must be taken into account above any formulas. For example, a senior dog that is given proper medical care could live longer than what is reflected in the estimate.
• The estimates given to mixed breed dogs are given according to the selected size group, and will not be an accurate estimate.
• This tool is not intended to replace the advice of your veterinarian. You must always consult your veterinarian regarding your pet’s specific health care needs.

The formula was derived from AVMA simplified guidelines. It only serves as a point of reference and not a diagnostic tool.

The age of your pet in human years is only a beginning point when determining how to talk to your veterinarian about your pet or share something entertaining about your pet with other owners. Knowing this number alone is not as meaningful when it comes to providing real care or attention for your pet.