What's the difference between a perpetual calendar and a yellow calendar?

A perpetual calendar is just a process for people to find a certain year, including many years. For example, if you want to know when the first day of February 2055 is, you can consult the perpetual calendar.

Generally, the lunar calendar is based on the lunar calendar, and the fortune calculated by China's eight diagrams and five elements will usually be used for a period of time. For example, if you get married this year and find a good day, just look at this year's lunar calendar.

Perpetual calendar Baidu definition: Perpetual calendar is the oldest solar calendar in ancient legends of China. In order to commemorate the achievements of calendar compilers for thousands of years, this kind of calendar was named "perpetual calendar".

Definition of the Gregorian calendar: The Gregorian calendar is an almanac that can simultaneously display various calendars such as the solar calendar, the lunar calendar and the dry calendar, and has a large number of rules and contents related to seeking good fortune and avoiding evil. In ancient times, the almanac was calculated and published by Qin, so it was also called the almanac. Its content guides the farming opportunities of Han working farmers, so it is also called the farmers' calendar. Han people are commonly known as general books. However, because the word "book" in Tongshu is homophonic with the word "lose", it is also called "Tong Sheng" because it is taboo.

The above is a reference.