How is a horse 12 years old in human year how would he be year?

There is no definitive answer to this question, as the conversion of horse years to human years is not an exact science. However, there are a few general guidelines that can be used. One common rule of thumb is that one human year is equivalent to approximately three horse years. This means that a 12-year-old horse would be roughly equivalent to a 36-year-old human.

However, it is important to note that this is just a general guideline, and there can be significant variation between individual horses. Some horses may age more slowly or quickly than others, and factors such as breed, diet, and environment can all play a role in a horse's lifespan.

Additionally, it is important to remember that horses and humans are different species with different lifespans. A 12-year-old horse may be considered to be middle-aged by horse standards, but they would still be relatively young compared to a human of the same age.