How old can a horse live in people years?

There's no perfect conversion for horse years to human years, but here's a common way to think about it:

* First 3 years: Each horse year is roughly equivalent to 3 human years.

* Years 4-10: Each horse year is about 4 human years.

* After 10 years: Each horse year is about 6-7 human years.

Example:

* A 10-year-old horse is roughly equivalent to a 42-year-old human.

* A 20-year-old horse is about 88-110 years old in human terms.

Important Note: This is just a general guideline. A horse's age in human years can vary depending on breed, health, and lifestyle.