只記得農曆生日，還能排八字嗎？

可以，但要先換成國曆日期。農曆日期本身無法直接定出月柱，因為月柱看的是節氣，不是農曆初一。換算還需要出生年份，否則同一個農曆日期會對到不同的國曆日。

農曆閏月會影響月柱嗎？

不會。月柱只看出生當時落在哪兩個節氣之間，閏月是農曆為了對齊朔望與回歸年所做的安排，不改變節氣的位置。

為什麼兩個排盤工具算出來的盤不一樣？

最常見的原因是出生時間剛好靠近節氣交接，或落在農曆年與立春之間，兩邊採用的換年、換月或換日規則不同。差異通常出現在年柱或月柱，而不是整張盤算錯。

I only know my lunar birthday — can I still get a chart?

Yes, but it has to be converted to a Gregorian date first. A lunar date alone cannot fix the month pillar, because the month pillar follows the solar terms, not the first day of a lunar month. The conversion also needs the year, or the same lunar date maps to different Gregorian days.

Does a leap lunar month change the month pillar?

No. The month pillar depends only on which pair of solar terms the birth falls between. A leap month is how the lunar calendar keeps in step with the solar year, and it does not move the solar terms.

Why do two tools disagree about my chart?

Usually the birth sits close to a solar term, or between Lunar New Year and Lichun, and the two tools apply different year-, month- or day-change rules. The difference normally shows up in the year or month pillar rather than the whole chart.

農曆生日可以直接排八字嗎？節氣與換月是怎麼算的

作者：Wei Chun Chuang・2026-10-24

很多人只記得自己的農曆生日，於是直覺認為八字就是「農曆的命盤」。其實八字的月柱不看農曆月份，而是看二十四節氣。這篇說明節氣怎麼決定月柱、立春換年的爭議，以及農曆生日要怎麼整理成能排盤的資料。

八字的月柱跟著節氣走

二十四節氣是把太陽一年的位置切成二十四段，立春、驚蟄、清明、立夏這些名稱就是節氣。八字的月份用的是其中十二個「節」作為分界：月柱在節氣當下那一刻換，不是農曆初一換，也不是國曆一號換。

舉例來說，寅月從立春開始，到驚蟄前結束；卯月從驚蟄開始。所以農曆正月初五出生的人，月柱可能還在前一個月，也可能已經換過，取決於立春在那一年落在幾號幾點。

年柱常見在立春換，但流派不同

八字的年柱也多數採立春換年，而不是農曆正月初一換年。這代表農曆新年過了、立春還沒到的那幾天，依這套規則年柱仍算前一年。

不過這點確實有不同說法：也有流派以農曆年初一為界，或在特定條件下另作處理。兩種主張在傳統文獻裡都找得到依據，本文不替讀者選邊。真正要記住的是：如果你出生在農曆年與立春之間，不同工具可能給你不同的年柱，而年柱換掉，連帶的生肖與相關推演也會不同。

日柱自己走六十甲子，不受曆法影響

日柱和月柱、年柱不一樣，它只是從甲子、乙丑一路排到癸亥，每天往前一格，六十天一輪，不中斷。農曆大小月、閏月、國曆平閏年都不會讓它跳號或停頓。它唯一的爭議是深夜換日的時點（晚上十一點或午夜），與曆法本身無關。

所以閏月不影響月柱

農曆每隔幾年會插入一個閏月，讓月份與季節不致脫節。既然月柱只問「出生那一刻落在哪兩個節氣之間」，閏月就不會讓月柱多一格或少一格。閏四月出生的人，月柱一樣照節氣判定。

排盤實際需要哪些資料

要排一張完整的八字，需要三樣東西：

國曆（西曆）出生日期。
出生時間，越精確越好，因為時辰決定時柱。
出生地點，用來處理時區與可能的真太陽時校正。

把記憶中的農曆生日換成國曆的做法是：

先確認出生年份，以及那一年是不是閏月、記的是不是閏月的那一個月。
用萬年曆或曆法換算工具查出對應的國曆日期。
再補上時間與出生地，一起交給排盤工具。

如果家裡的紀錄只寫農曆而沒有年份，或連農曆月份都不確定，誠實的結論是資料不足，而不是硬挑一個日期。

為什麼兩個工具會算出不同的盤

多數情況下不同工具結果一致，會不一致的通常是以下幾種邊界：

出生時刻離節氣交接只差幾小時：節氣有精確到分鐘的時刻，取整天或取精確時刻會得到不同月柱。
出生在農曆年與立春之間：換年規則不同，年柱就不同。
出生在深夜子時：換日規則不同，日柱不同。
是否做真太陽時校正、是否還原日光節約時間。

遇到這種情況，比較有用的問法不是「哪個工具對」，而是「這個工具採用哪一套規則」。知道規則，就能理解兩張盤為什麼長得不一樣，也知道該用哪一張來學習。

常見問題

只記得農曆生日，還能排八字嗎？: 可以，但要先換成國曆日期。農曆日期本身無法直接定出月柱，因為月柱看的是節氣，不是農曆初一。換算還需要出生年份，否則同一個農曆日期會對到不同的國曆日。
農曆閏月會影響月柱嗎？: 不會。月柱只看出生當時落在哪兩個節氣之間，閏月是農曆為了對齊朔望與回歸年所做的安排，不改變節氣的位置。
為什麼兩個排盤工具算出來的盤不一樣？: 最常見的原因是出生時間剛好靠近節氣交接，或落在農曆年與立春之間，兩邊採用的換年、換月或換日規則不同。差異通常出現在年柱或月柱，而不是整張盤算錯。

想用 App 練習？

想看自己的生日落在哪個節氣區間，時來－八字是一款教你讀八字的 iPhone 課程 App，四柱由 App 計算。目前已送 App Store 審核，尚未上架，還不能下載。想先試的話，網頁版免註冊、免登入即可排出命盤，並附二十堂課，可以邊排邊確認換月的位置。

更多入門文章・英文版

Can you build a Bazi chart straight from a lunar birthday?

作者：Wei Chun Chuang・2026-10-24

Many people only remember their lunar birthday and assume Bazi is therefore "the lunar calendar chart". In fact the month pillar does not follow lunar months at all; it follows the twenty-four solar terms. This article explains how solar terms set the month pillar, the disagreement about changing the year at Lichun, and how to turn a remembered lunar birthday into usable data.

Month pillars follow the solar terms

The twenty-four solar terms divide the sun's yearly path into twenty-four segments; Lichun, Jingzhe, Qingming and Lixia are solar term names. Bazi months use twelve of them as boundaries: the month pillar changes at the moment of the solar term, not on the first day of a lunar month and not on the first of a Gregorian month.

For example, the Yin month begins at Lichun and ends just before Jingzhe; the Mao month begins at Jingzhe. So for someone born on the fifth day of the first lunar month, the month pillar may still be the previous one or may already have turned, depending on the date and time of Lichun that year.

The year commonly changes at Lichun, but schools differ

Most practice also changes the Bazi year at Lichun rather than at Lunar New Year. That means in the days after Lunar New Year but before Lichun, this rule still counts the outgoing year pillar.

There is genuine disagreement here: some schools use the first day of the lunar year as the boundary, or handle particular cases differently. Both positions can be traced in traditional sources, and this article does not choose for you. What matters is this: if you were born between Lunar New Year and Lichun, different tools may give you different year pillars, and a changed year pillar also changes the year animal and anything derived from it.

The day pillar runs its own sixty-day cycle

Unlike the month and year pillars, the day pillar simply counts from Jia-Zi and Yi-Chou through to Gui-Hai, advancing one step each day, sixty days per round, without interruption. Long and short lunar months, leap months and Gregorian leap years never make it skip or pause. Its only point of contention is when the day turns late at night (11 p.m. or midnight), which has nothing to do with either calendar.

So leap months do not shift the month pillar

Every few years the lunar calendar inserts a leap month to keep months aligned with the seasons. Since the month pillar only asks which pair of solar terms the birth falls between, a leap month adds no extra pillar and removes none. Someone born in a leap fourth month still has their month pillar decided by the solar terms.

What a chart actually needs

要排一張完整的八字，需要三樣東西：

A Gregorian (solar) date of birth.
A time of birth, as precise as possible, because the double-hour fixes the hour pillar.
A birthplace, used for the time zone and any mean-solar-time correction.

把記憶中的農曆生日換成國曆的做法是：

Establish the year of birth, whether that year had a leap month, and whether the remembered month was the leap one.
Look up the matching Gregorian date with a perpetual calendar or a conversion tool.
Add the time and the birthplace, and give all three to the chart tool.

If the family record gives a lunar date with no year, or the lunar month itself is uncertain, the honest conclusion is that the data is insufficient — not that you should pick a plausible date.

Why two tools can disagree

Most of the time tools agree. Disagreement clusters around a few boundaries:

A birth only hours from a solar term: terms have a time to the minute, so rounding to the day or using the exact moment can yield different month pillars.
A birth between Lunar New Year and Lichun: different year-change rules, different year pillar.
A birth in the late-night Zi hour: different day-change rules, different day pillar.
Whether mean solar time is corrected for, and whether daylight saving has been undone.

In these cases the useful question is not "which tool is right" but "which rule does this tool use". Once you know the rule, you can see why two charts differ and decide which one you are learning from.

常見問題

I only know my lunar birthday — can I still get a chart?: Yes, but it has to be converted to a Gregorian date first. A lunar date alone cannot fix the month pillar, because the month pillar follows the solar terms, not the first day of a lunar month. The conversion also needs the year, or the same lunar date maps to different Gregorian days.
Does a leap lunar month change the month pillar?: No. The month pillar depends only on which pair of solar terms the birth falls between. A leap month is how the lunar calendar keeps in step with the solar year, and it does not move the solar terms.
Why do two tools disagree about my chart?: Usually the birth sits close to a solar term, or between Lunar New Year and Lichun, and the two tools apply different year-, month- or day-change rules. The difference normally shows up in the year or month pillar rather than the whole chart.

Practise with an app

To see which solar term window your birthday falls in, Shilai – Bazi is an iPhone course that teaches you to read Bazi, with the four pillars calculated for you. It is currently in App Store review and not yet released, so it cannot be downloaded. In the meantime the free web version builds a chart with no sign-up or login and includes 20 lessons, so you can check where the month changes as you go.

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