How to Convert a Horse's Age to Human Years

The average life expectancy of a well-cared-for horse is about 30 years, while ponies and miniature horses live to 35 years on average. Horses may show signs of aging in their late teens, and ponies within their early twenties. However, with proper feeding and access to veterinary care, horses and ponies can live into their forties.

Horses mature faster than humans in their early years, and then age more slowly once they reach adulthood. Thus, you cannot convert horse years to human years by multiplying the horse's age by a factor. To convert a horse's age to its equivalent human age, use the method outlined below, or use the conversion calculator on the left.

Horse's Age at Birth

At birth, a horse can already walk and run, so a 0 year old horse is equivalent to a 2 year old human.

One Year Old Horse

A 1 year old horse has the equivalent maturity of an 8 year old human.

Two Year Old Horse

At 2 years of age, a horse begins puberty and transitions from being a child to an adult. In terms of physical and emotional maturity, a 2 year old horse is equivalent to a 13 year old human.

Three Year Old Horse

At 3 years of age, a horse or pony can reproduce. The human age equivalent is 17 years. This is the last year that a female horse can be called a filly, or that a male horse can be called a colt.

Four Year Old Horse

A 4 year old horse is equivalent to a 20 year old human. A female horse aged 4 or more is called a mare. A male horse aged 4 or more is called a stallion, unless he has been castrated. Castrated male horses are called geldings.

Older Than Four Years

In the case of horses, for every year after the fourth year, add 2.5 human years. In the case of ponies or miniature horses, add 2 human years for every year after the fourth year.

Examples:

Chester is a 8 year old horse. In human years, his age is

20 + 2.5 + 2.5 + 2.5 + 2.5 = 30.

Hilda is an 16 year old pony. In human years, her age is

20 + 12(2) = 44.

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