365-day calendar facts for kids

A 365-day calendar is a type of calendar that always has exactly 365 days in a year. This is different from many calendars, like the one we use today, which sometimes add an extra day (a leap day) to keep time accurate.

What is a 365-Day Calendar?

This kind of calendar is often used in computer programs. It helps with calculations where you need a set number of days for each year. For example, if you want to find a daily cost, you might divide a yearly total by exactly 365.

How Banks Use It

Some banks also use a 365-day calendar. They use it to figure out how much Interest you earn or owe on your money. This means they calculate interest based on a year having exactly 365 days.

Ancient Calendars Without Leap Years

Some ancient calendars also used a fixed 365-day year. These calendars did not have a leap year rule. This meant that over time, the calendar dates would slowly shift away from the actual seasons.

Mesoamerican Calendars

For example, some calendars from ancient Mesoamerica worked this way. These include the Maya Haab' calendar and the Aztec Xiuhpohualli calendar. Because they didn't add leap days, their calendar dates gradually moved out of sync with the seasons.

Zoroastrian Calendars

Some versions of the Zoroastrian calendar also used a fixed 365-day year. They did not have rules for adding leap days. Even though people knew about leap year rules by the 800s AD, some versions still didn't use them. The Qadimi version, still used today, has no leap rule. The Shahanshahi version added one leap month a long time ago, but no leap years since. The Fasli version, created in the 1900s, does add one day every four years.

See also

• 360-day calendar