Two traditions, one verdict. The Western sky and the Chinese almanac, asked the same question — and shown where they agree.
Every day from 1900–2100 computable · 73,000 days · 12 Day Officers · 15 undertakings
For as long as people have begun important things — marriages, ventures, journeys, buildings — they have asked whether the moment was right. Two of the world's great traditions answer that question in parallel, and this calculator runs both.
Western electional astrology reads the sky above the chosen moment. It asks: is the Moon waxing (favoring growth) or waning (favoring release)? Is Mercury retrograde, complicating contracts and communication? Which planet rules the weekday, and is the planet that governs your activity — Venus for love, Mercury for commerce — well placed? An "election" is literally a chart cast for a time you are free to choose, selected so its sky supports what you intend.
Chinese date selection, called 择日 (zé rì), reads the same question through the almanac — the 黄历 / 通勝. Every day in the almanac carries a verdict: what it favors (宜) and what it forbids (忌). The backbone of that verdict is the cycle of the 12 Day Officers (建除十二神) — a twelve-day rotation in which each day is governed by an "officer" with its own temperament.
Electional astrology reads the heavens over your chosen moment — the Moon's phase and sign, whether Mercury or Venus runs retrograde, and which planet rules the weekday against the one that governs your act.
择日 reads the same day through the 建除 cycle of Day Officers — each marking the day 宜 (favorable) or 忌 (avoid) for specific acts — plus whether the day clashes with your own zodiac animal.
This calculator runs both at once and blends them into a single verdict — showing you where the two traditions agree, where they split, and which one is speaking louder for your particular choice.
No lookup tables of pre-baked "lucky days" — the verdict is computed from astronomy and the classical almanac rule for your exact date.
Lunar and solar longitude from the same Meeus-based engine that powers our birth-chart tools — accurate to a fraction of a degree, recomputed for every date.
Derived the classical way: the relationship between the day's earthly branch and the branch of the solar month — including the authentic doubling at each solar term (节).
Mercury and Venus retrograde periods for 2025–2028 are built in, so contract, travel and wedding warnings fire on the right dates.
Your birth date sets your 立春-adjusted zodiac animal; days carrying the opposing branch are flagged as a personal clash, the way a traditional date-picker would.
Each day belongs to one officer in a fixed twelve-day cycle. The officer is set by how the day's earthly branch relates to the branch of the solar month. Here is what each favors:
| 建 Establish | Beginnings, proposals, starting a venture or journey, breaking ground on a plan. Avoid moving house and burials. |
| 除 Remove | Clearing, cleansing, medical treatment, ending what is stale. A day to remove, not to build. |
| 满 Full | Openings, signing agreements, housewarmings, gatherings — seeking abundant return. Avoid burials. |
| 平 Balance | Marriages, road and construction work, leveling and negotiation. Steady and fair. |
| 定 Stable | Long-term commitments — weddings, settling agreements, launching what should last. |
| 执 Initiate | Signing, taking hold, new projects. Avoid moving and opening a storefront. |
| 破 Destruction | The breaking day. Good only for demolition and endings; avoid everything constructive. |
| 危 Danger | Caution. Avoid risk, travel, heights and water. A day for prayer, not ventures. |
| 成 Success | The most auspicious officer. Marriages, openings, moving, nearly everything favorable. |
| 收 Receive | Gathering in — acquiring wealth, closing deals, asking for a raise, enrolling, hiring. |
| 开 Open | Opening — a business, a home, a new role, a wedding. Welcoming. Avoid burials. |
| 闭 Close | Sealing and ending. Good for burials and finishing; avoid weddings, openings, travel. |
The Western reading computes the Moon's phase and sign for your date, checks whether Mercury (and, for weddings, Venus) is retrograde, and weighs the planetary ruler of the weekday against your activity. The Chinese reading derives the day's Day Officer from its earthly branch and the solar month, then matches that officer's favored and forbidden activities to yours. The combined verdict blends both — and, if you add your birth date, penalizes days that clash with your zodiac animal.
The astronomy is computed, not looked up — Moon phase and sign from the same engine that powers our birth-chart tools, and the Day Officer from the classical 建除 rule. Mercury and Venus retrograde windows are drawn from a built-in table for 2025–2028. The free tier reads the day itself, which is the same for everyone. The personalized layer reads the day against you.
Because they measure different things — one the sky, one the calendar's own cycle. When both agree a day is strong, that is the clearest signal. When they split, the calculator shows you exactly why, so you can weigh which tradition matters more to you for this particular choice.
Most milestones have some flex — a wedding within a season, a launch within a month. Use Find Best Days to scan your window and let the calculator surface the strongest options. Even when the date is fixed, knowing the conditions lets you work with them rather than against them.
Cosmos Daily offers these readings for reflection and cultural insight. Electional astrology and 择日 are interpretive traditions, not predictive science. Use them as one input among many for meaningful decisions.
The full Seven-System reading places your timing inside Western astrology, Bazi, Sabian Symbols, Hermetic Alchemy, the Tree of Life and the Hermetic Virtues.
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