Bidirectional Gregorian ↔ Chinese lunar converter. Full lunar date (干支), zodiac, 纳音 element. Leap-month aware.
Lunar / Solar Date Converter
How to use
Pick a direction
Toggle "Gregorian → Lunar" or "Lunar → Gregorian". Default is Gregorian-to-Lunar.
Enter a date
Year + month + day. Supported range 1900-2100. Click "Today" to load the current date.
Leap-month checkbox (Lunar→Gregorian only)
Some lunar years have a leap month. If the target year has a leap month + you mean the leap one, tick the box. The tool tells you whether the year has a leap month at all.
Read the result
You get: matched date, zodiac, stem-branch (year/month/day), and 纳音 sound-element. All computed via 寿星 astronomy formulae — no network required.
The Chinese Lunar Calendar: A Lunisolar Masterpiece
The Chinese lunar calendar (农历, also 夏历 or "old calendar") is one of the world's most precise lunisolar calendars still in active use. It tracks both the solar year (for the 24 agricultural seasonal terms) AND lunar months (for tides + festivals), staying in sync via carefully-engineered "leap months." This tool uses the public-domain Shouxing astronomical algorithm — a complete implementation of the lunisolar formulae — to do bidirectional conversion for any date from 1900 to 2100, entirely in your browser.
What's a leap month?
A solar year (365.24 days) and 12 synodic months (354.36 days) differ by about 11 days per year. Without compensation, Chinese New Year would drift into summer over a few decades. The lunar calendar fixes this by inserting 7 leap months every 19 years (the "七闰法" rule). 2025 has a leap 6th month, for example. This tool auto-detects whether a target year has a leap month and prompts accordingly.
干支 (stem-branch), 生肖 (zodiac), 纳音 (sound-element)
Each lunar year maps to: a stem-branch pair (60-year cycle, e.g. 2026 = 丙午); a zodiac animal (12-year cycle, 2026 = horse 马); a 纳音 sound-element (60-year cycle, 2026 = 天河水 "celestial-river water"). These three cycles serve different roles in folk custom, fortune-reading (bazi), and date-selection (择日学). The tool returns all three side-by-side.
ASEAN Chinese-community uses
Chinese communities in Singapore, Malaysia, Indonesia, and the Philippines still observe the major lunar festivals: Chinese New Year, Lantern, Qingming, Dragon Boat, Qixi, Ghost Festival, Mid-Autumn, Double Ninth, Winter Solstice. Each falls on a different Gregorian date each year. This tool answers "when does Chinese New Year fall in 2027?" instantly, and also handles the reverse — converting parents'/grandparents' lunar birthdays into Gregorian for civil registration.
10 Facts about the Chinese Lunar Calendar
The Chinese lunar calendar has been in use for 4000+ years. The Xia dynasty (~2100 BCE) had a primitive version; Shang oracle-bone inscriptions show complete lunar-phase records.
Inserting 7 leap months every 19 years (the "七闰法" rule) keeps the lunar calendar in sync with the solar year more precisely than the Gregorian calendar's every-400-years correction.
The 24 solar terms are the lunar calendar's SOLAR component — divided every 15° of solar longitude, independent of lunar months. Start of Spring, Summer Solstice, Autumn Equinox, Winter Solstice are the 4 most important.
There is no "leap first month" — the first month must contain the Start of Spring solar term, so it cannot repeat. Leap months can be any month from 2 to 12.
2025 has leap 6th month; 2028 leap 5th; 2031 leap 3rd. The distribution looks random but follows strict astronomy — no human adjustment is possible.
HK Observatory and mainland China's Purple Mountain Observatory occasionally disagree by 1 day — when a new moon falls exactly across midnight. Happens roughly once every 30 years.
The zodiac year aligns with the lunar new year (2026 CNY = 2026-02-17, after which the Horse year begins) — NOT with Gregorian New Year. Babies born 2026-01-15 are Snake (2025's zodiac), not Horse.
纳音 (sound-element, 60-year cycle) pairs with stem-branch — every 2 consecutive years share the same 纳音 (2026 丙午 = 天河水, 2027 丁未 = 天河水). It's a foundational concept in 大六壬 and 紫微斗數 fortune-reading systems.
This tool supports 1900-2100 — the 200-year high-precision window of the Shouxing algorithm. Beyond that range it still computes, but may differ from official almanacs by 1 day in rare edge cases, so it's not exposed by default.
Vietnam, Korea, and Japan all historically used the Chinese lunar calendar. Vietnam still does (calls it 农历). Korea retains it for Lunar New Year + Mid-Autumn. Japan switched to Gregorian during the Meiji Restoration but keeps the old calendar as reference.
Frequently Asked Questions
-
Yes — any lunar date maps to exactly one Gregorian date (computed at UTC+8, Purple Mountain Observatory China). This tool defaults to that timezone.
-
This tool supports 1900-2100. Pre-1900 lunar dates follow dynasty-specific historical calendar rules that differ from the modern Shouxing algorithm. For pre-1900 dates, consult academic Chinese chronological tables.
-
Custom varies by region. Common practices: (1) celebrate the leap month in leap years, the regular month in non-leap years; (2) always use the regular month; (3) celebrate twice in leap years. The tool doesn't decide for you — it just tells you when the next leap of that month occurs.
-
They are independent systems. The Chinese lunar calendar is the civil one. Buddhist calendar starts from Buddha's nirvana (~544 BCE). Taoist calendar starts from the Yellow Emperor. Some Buddhist/Taoist festivals USE lunar dates, but the year-numbering systems are completely different.
-
UTC+8 (China Standard Time) — the canonical lunar-calendar timezone used by mainland China, HK, Taiwan, Singapore, and Malaysia. Even if you're in Europe/US, the lunar date shown is UTC+8.
-
Chinese zodiac is assigned by lunar year (12-year cycle); Western astrology is by Gregorian birth date (12 monthly signs). They're parallel systems with no overlap. Chinese people typically know both their 生肖 and their Western sign.
-
The tool returns year + month + day 干支 simultaneously. Year 干支 drives zodiac + 纳音 lookups; month + day 干支 feed bazi calculations. For hour-level 干支 (needed for full bazi), see RT-CHN-001 (Bazi Chart Calculator).
-
No. All conversion happens in your browser. No server calls. RECATOOLS applies zero-tracking + zero-storage to every tool input across the entire site.
-
Shouxing astronomical algorithm — a public-domain implementation of modern astronomical formulae (lunar phase, solar ecliptic longitude, solar-term computation). 99.99% match with Purple Mountain Observatory tables. Source is fully auditable: this tool uses lunar-javascript (MIT-licensed).
-
Use Lunar→Gregorian, input "year=target, month=1, day=1" — that's lunar 正月初一 = Chinese New Year. Or use our dedicated CNY-date tool RT-CHN-050 for past + future CNY dates in one view.
Related News
You may be interested in these recent stories from our newsroom.
No related news yet for this tool. Our editorial team publishes new pieces every week.
Browse all news →75 more free tools
Calculators, converters, security tools — no signup.