Perpetual Calendar is an application for Vietnamese people to have an accurate calendar of lunar and solar days. It's very useful to know when to plant trees, flowers, or other types of plants for your garden. You can find out when to do the various activities such as washing your clothes, cleaning your house, etc. You can also get detailed information about the current Vietnamese lunar calendar.

For example, on the current day of the 12th lunar month, you can find out the zodiac sign, the black day, etc. You can also see the current Vietnamese year and the next year for the year that is currently being used.