What Calendar Do We Use In The Us. Solar calendars, such as the gregorian calendar, are based on the earth’s rotation around the sun in a year. It was first used in 1582, as an evolution of what already existed, enabling people to understand the year and season with.

First, using a calendar assists us with creating routine in our day. So next time you flick over to a different month on your calendar, take a moment to appreciate the vast array of calendars used across the globe.