Question 1

Is the 7-year rule for dog age accurate?

Accepted Answer

No, the old 7:1 ratio is a myth. Dogs age much faster in their first two years — about 15 human years in the first year alone. After that, the rate varies by breed size, with larger breeds aging faster than smaller ones.

Question 2

Why does breed size affect a dog's human age equivalent?

Accepted Answer

Larger dogs have shorter lifespans and age faster after maturity. A Great Dane is considered senior around age 6, while a Chihuahua may not reach senior status until age 10-11. Scientists believe this is related to faster cellular aging in larger breeds.

Question 3

At what age is a dog considered a senior?

Accepted Answer

It depends on breed size. Small dogs (under 20 lbs) are generally senior around 10-12 years. Medium dogs around 8-10 years. Large dogs around 7-8 years. Giant breeds can be considered senior as early as 5-6 years old.

Question 4

How are dog years calculated for puppies?

Accepted Answer

The first year of a dog's life equals roughly 15 human years regardless of breed size. The second year adds about 9 more human years (reaching 24). After that, each additional year adds 4-7 human years depending on the breed size.

Question 5

Do mixed breed dogs age differently than purebreds?

Accepted Answer

Mixed breed dogs tend to live slightly longer than purebreds on average, likely due to greater genetic diversity. For mixed breeds, use the size category closest to your dog's weight for the most accurate age conversion.

Dog Age	Small	Medium	Large	Giant
1 year	15	15	15	15
2 years	24	24	24	24
3 years	28	29	30	31
4 years	32	34	36	38
5 years	36	39	42	45
6 years	40	44	48	52
7 years	44	49	54	59
8 years	48	54	60	66
9 years	52	59	66	73
10 years	56	64	72	80
11 years	60	69	78	87
12 years	64	74	84	94
13 years	68	79	90	101
14 years	72	84	96	108
15 years	76	89	102	115

Dog Age Calculator

How It Works

Dog Age to Human Age Reference Table

Frequently Asked Questions