Chinese perpetual calendar (萬年曆). Browse any month from 1900-2100 in a Gregorian + lunar grid; navigate with ◀▶ or the year/month selectors. Each cell shows the Gregorian day, lunar day (lunar month name on 初一), and 节气/festival markers. Tap a day for the full almanac: lunar date, stem-branch, zodiac, 宜/忌, clash, 煞, 建除, 廿八宿, solar term, festivals.
Chinese Perpetual Calendar (萬年曆)
How to use
Browse a month
The calendar opens on the current month. Use ◀ / ▶ to step to the previous or next month, or jump straight to any month from 1900-2100 with the Year and Month dropdowns. "Back to today" returns to the current month anytime.
Read a day cell
Each cell shows the Gregorian day (large) with the lunar day beneath it. On lunar 初一 the cell shows the lunar month name (e.g. 五月) so you can see exactly where the lunar month changes over. Sundays and Saturdays are tinted amber.
Spot solar-term + festival markers
If a day is one of the 24 solar terms, a green tag appears (e.g. 夏至 Summer Solstice); a traditional festival shows a red tag. Most days have neither — blank is normal.
Open a day's almanac
Tap any day and the detail panel below expands that day's full 老黃曆: Gregorian + lunar date, year/day stem-branch, zodiac, plus 宜 (do), 忌 (avoid), clash, 煞, 建除, 廿八宿 (with luck), fetus-spirit, nine-star, solar term, and festivals. Everything is computed locally in your browser.
The Chinese Perpetual Calendar (萬年曆): A Browsable Lunisolar Almanac
A 萬年曆 ("ten-thousand-year calendar") does not literally span ten thousand years — the phrase is a Chinese idiom for a general-purpose almanac you can page through to look up any year and month. Unlike a single-date converter, it lays a whole month out as a grid so you can see, at a glance, every day's Gregorian date, its lunar date, which days are solar terms, and which fall on traditional festivals. This tool reproduces exactly that form: it opens on the current month, lets you flip with ◀ / ▶ or jump anywhere with the Year and Month dropdowns, and covers a full two centuries from 1900 to 2100. Every calculation runs locally in your browser — no network calls, no model.
What makes a perpetual calendar so useful is that it shows "the calendar of the sun" and "the calendar of the moon" side by side. The Gregorian calendar is purely solar, so its dates line up with the seasons. The Chinese lunar calendar is lunisolar: its months follow the phases of the moon, while leap months and the 24 solar terms quietly pull the sun's pace back into step. When a cell shows the lunar month name on 初一 (the first lunar day, e.g. 五月 "fifth month"), you are literally seeing a new moon — the first day of each lunar month is the day of the new moon. Stacking both systems on one grid makes it intuitive why Chinese New Year, Dragon Boat, and Mid-Autumn land on different Gregorian dates each year, and lets you answer questions like "when is Qingming next year?" in a glance.
Solar terms, festivals, and the daily almanac
This calendar embeds two kinds of marker into each cell. Green tags are the 24 solar terms — Start of Spring, Spring Equinox, Summer Solstice, White Dew, Winter Solstice and so on. These are fixed points on Earth's orbit around the sun, the genuinely astronomical component of the lunar calendar, and there are exactly 24 of them a year. Red tags are traditional festivals such as Chinese New Year, Lantern, Dragon Boat, Qixi, Ghost Festival, Mid-Autumn, Double Ninth, and Winter Solstice, whose dates are fixed by the lunar calendar. Tap any day and the detail panel expands that day's complete 老黃曆: year and day stem-branch, zodiac, 宜 (activities to do), 忌 (activities to avoid), the day's clashing zodiac sign and inauspicious direction, the 建除 twelve day-officers, the 廿八宿 lunar mansion with its luck reading, the fetus-spirit position, and the day and year nine-star. This do-and-avoid system descends from the Qing-dynasty imperial 《协纪辨方书》 and sits at the heart of Chinese date-selection culture.
"A calendar exists to mark the four seasons, follow the way of heaven, and give the people their time." Aligning the steps of the sun and the moon has been the perpetual calendar's job for centuries.
Cultural stance + disclaimer
A perpetual calendar is a calendrical tool, and its most reliable parts — Gregorian dates, lunar conversion, the 24 solar terms, zodiac and stem-branch — rest on precise astronomical formulae, so you can rely on them for checking festivals, cross-referencing birthdays, and planning trips. But the 宜忌 and 神煞 you see after tapping a day are a different matter: they are folk tradition with no scientific basis, and different almanacs routinely disagree on the same day's do-and-avoid lists. This tool uses an embedded open-source 通書 algorithm (the 6tail implementation), so its output may differ slightly from a paper almanac on your shelf — that is normal, because date-selection has many competing schools and no single authoritative answer. Treat the calendar as a handy calendrical reference and cultural cross-check; for real-life milestones — weddings, business openings, moving house — rely on practical conditions, professional advice, and family coordination rather than any single day's 宜忌. RECATOOLS applies zero-tracking and zero-storage to every date you enter: all computation stays on your own device.
10 Facts about the Perpetual Calendar
萬年曆 ("ten-thousand-year calendar") is an idiomatic exaggeration meaning "a general almanac for any year/month" — not a literal 10,000 years. This tool's precise window is the 200 years from 1900 to 2100.
A folk legend ties the name to a calendar-maker called "Wan Nian" (萬年) who measured time with sun-shadows and water-clocks; later generations named the perpetual calendar after him — a tidy story for why 萬年 (ten-thousand-years) stuck.
The first day of every lunar month (初一) is always the new moon (合朔). That's why this calendar prints the lunar month name on 初一 — you're literally watching the moon reset.
The 24 solar terms are the lunar calendar's "solar half": defined every 15° of the sun's ecliptic longitude, independent of the moon. So they fall on nearly the same Gregorian date each year (Winter Solstice is always Dec 21-23).
The lunar calendar inserts 7 leap months every 19 years to catch the moon up with the sun. Leap months have no fixed slot — they follow strict astronomy (2025 has a leap 6th month, 2028 a leap 5th).
This grid starts the week on Sunday, matching most printed Chinese perpetual calendars; the Sunday and Saturday columns are tinted amber so weekends are easy to spot.
The zodiac changes with the lunar year (lunar 正月初一), not Gregorian New Year. A baby born in January before the lunar new year carries the previous year's zodiac sign.
The 老黃曆 宜忌 in this calendar come from an embedded 通書 algorithm (the open-source 6tail implementation), whose 神煞 system traces back to the Qing imperial 《协纪辨方书》 of 1742.
Different almanacs routinely disagree on the same day's 宜忌, because date-selection has competing schools that weigh the 神煞 differently. A small difference from your paper almanac is normal, not an error.
ASEAN Chinese communities still page through perpetual calendars to find festivals and auspicious days — Hong Kong's 通勝 and the lunar desk calendars of Singapore and Malaysia share this tradition. This tool brings the whole-month view to your browser, offline.
Frequently Asked Questions
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No — "ten-thousand" is hyperbole for "a general almanac you can page through". This tool supports 1900-2100 (200 years), the high-precision window of the underlying astronomy. It can compute beyond that, but may differ from official tables by a day, so it's not exposed by default.
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The converter looks up one date at a time; the perpetual calendar lays a whole month out as a grid you can page through — seeing every day's lunar date, solar terms, and festivals at once, then tapping any day for the full almanac. One is lookup; this is browse.
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The first day of each lunar month is 初一, the new moon. To show where the lunar month rolls over, the calendar prints the lunar month name on 初一 cells (e.g. 五月) instead of "初一"; other days show the lunar day (初十, 廿二, etc.).
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There are only 24 solar terms a year and festivals fall on specific days, so for most dates a cell genuinely has neither — blank is normal. A green or red tag only appears when that exact day is a solar term or festival.
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The 宜忌 are folk tradition with no scientific basis — a thousand-year-old custom, but "which day is good for what" cannot pass modern statistical scrutiny. This tool does not endorse their validity; they're for cultural + entertainment reference only.
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Because date-selection has multiple schools that weigh the 神煞 differently, almanacs routinely disagree on a given day. This tool uses an embedded open-source 通書 algorithm (6tail), so it may differ slightly from some printed almanacs — that's normal, and there's no single correct answer.
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Use the Year and Month dropdowns in the control bar — the grid jumps to that month instantly. You can also step month-by-month with ◀ / ▶, or click "Back to today" to return to the current month. Range: 1900-2100.
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UTC+8 (China Standard Time) — the canonical lunar-calendar timezone used by mainland China, Hong Kong, Taiwan, Singapore, and Malaysia. Even if you're in Europe or the US, the lunar dates, solar terms, and festivals shown are at UTC+8.
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The content is identical; only the script differs. In Traditional (zh-TW) mode the 宜忌, solar-term, zodiac, and 神煞 terms convert automatically to Traditional characters (e.g. 沖 not 冲, 穀雨 not 谷雨) for readers in Hong Kong, Taiwan, and overseas.
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No. All calendar and almanac computation runs locally in your browser — no network requests, no model calls. RECATOOLS enforces zero-tracking + zero-storage for these inputs.
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