Lunar / Solar converter
Two-way conversion between Vietnamese lunar and solar calendars.
Tips
For automatic anniversary reminders every year (lunar + solar), use the ForLife app — enter once, get reminded forever. Free, works offline.
Try ForLife free →Frequently asked questions
How are lunar and solar calendars different?
The Gregorian (solar) calendar follows Earth’s orbit around the Sun (365–366 days). The lunar calendar follows the Moon’s phases — each month is 29 or 30 days. Vietnam’s lunar calendar adds occasional leap months to keep the lunar year aligned with the solar year.
What is a lunar leap month?
Every 2–3 years the lunar calendar inserts a leap month (the same month name appears twice in a row) to make up the ~11-day shortfall between the lunar year (354 days) and solar year (365 days). For example, a year with "leap 5" has two consecutive lunar 5th months.
Can the tool convert in both directions?
Yes. Enter a solar date to get the lunar equivalent (with sexagenary cycle), or enter a lunar day/month/year (and the leap flag if applicable) to get the solar date.
Does this tool send anniversary reminders?
This page is a one-shot converter. To get auto-reminders for lunar anniversaries every year, install the ForLife app — enter the date once and the system pushes reminders forever.
How accurate is it, and what year range?
Uses the canonical Hồ Ngọc Đức algorithm (Vietnam UTC+7). Verified for 1900–2100.