Is birthday accurate in lunar calendar or solar calendar? Why?

The lunar calendar is only used in a few countries, and the solar calendar is more widely used. "Bacon said: existence is truth". Since so many countries use it, there must be a reason.

In fact, the lunar calendar is not very accurate, just because it is in the traditional sense of China, so it has been handed down. Because the lunar calendar often has leap months, such as twelve months a year. If there is a leap month, a year is thirteen months. Just like the solar calendar, a year always lingers on 365 or 366.

Nowadays, children's birthdays don't use the lunar calendar, but the solar calendar. I think more people will use the solar calendar for their birthdays in the future.