Do I enter my lunar or solar birthday for a saju reading?

Enter your solar (Gregorian) birth date — the date on your passport or birth certificate. Korean saju is calculated on the solar calendar and uses the 24 solar terms to fix the month pillar. If you only know a lunar date, do not type it as if it were solar; instead pick the calendar that matches the date you have, and let the calculator convert it. Mixing them up is the single most common reason a chart turns out wrong.

If saju is traditional, why is it not the lunar calendar?

It is a common misconception. While the lunar calendar is part of Korean tradition, the saju month pillar is set by the sun, not the moon. The year is divided by the 24 solar terms — for example the month pillar changes around the Beginning of Spring rather than at the lunar new year. So the underlying clock of saju is solar. The lunar date is only useful as a reference you convert from, not as the value the chart is built on.

My family gave me a lunar birthday. How do I convert it?

You do not need to do the math by hand. In a good calculator you select the calendar your date belongs to — lunar or solar — and the tool converts it to the correct solar date and applies the solar terms automatically. If you were told a lunar date and also need to handle a leap month, choose the lunar option and mark the leap month so the conversion lands on the right day. The Cheonmyeongdang chart handles both.

What is a leap month and does it matter for saju?

The lunar calendar occasionally inserts an extra month, called a leap month, to stay aligned with the seasons. If your lunar birthday falls in a leap month and you ignore that flag, the conversion can land on the wrong solar date and shift your pillars. When you enter a lunar date, always note whether it was a leap month so the chart is built on the correct day.

I was born near the start of a month — could the wrong calendar change my chart a lot?

Yes, this is where errors do the most damage. The month pillar changes at a solar term, not on the 1st of the month, so a birth near a boundary can flip the entire month pillar — and with it the seasonal reading of your Day Master, your element balance and parts of your timing. If you are born within a day or two of a solar term, getting the calendar and the conversion exactly right matters more than for anyone else.

Where can I get an accurate saju chart with the right calendar handling?

Cheonmyeongdang lets you choose solar or lunar for your birth date, handles leap months, and applies the 24 solar terms to fix your month pillar correctly. You get your Day Master and Five Elements distribution in plain English, built on the right date rather than a mixed-up one. You can start free and decide afterward whether to go deeper.

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The wrong calendar is the number-one reason a saju chart comes out wrong. People type a remembered lunar birthday as if it were a solar one — and quietly get someone else's chart. The short answer: enter your solar (Gregorian) date, the one on your passport. Korean saju is built on the solar calendar and the 24 solar terms. This guide explains why, how a lunar date is converted, where leap months and solar-term boundaries trip people up, and how to get an accurate chart free, in plain English.

The one-line answer

For Korean saju, enter your solar (Gregorian) birth date — the date on your passport or birth certificate. If the only date you have is a lunar one, do not type it into a solar field; instead choose the lunar option so the tool converts it for you. The chart is always built on the solar calendar underneath, because the saju month pillar is set by the sun.

Rule of thumb: pick the calendar that matches the date you actually have, and let the calculator convert. The danger is never "which calendar is correct" — it is entering a lunar date as if it were solar, or vice versa.

Why saju is solar, not lunar

Many people assume that because saju is old and Korean, it must run on the lunar calendar. It does not. The four pillars — year, month, day and hour — are anchored to the 24 solar terms, the points that mark the sun's journey through the year. The month pillar changes at a solar term such as the Beginning of Spring, not at the lunar new year. So the underlying clock of saju is solar; the lunar date is only a reference you convert away from.

What you have	What to do	Why
Passport / ID date	Enter as solar	Modern documents use the Gregorian (solar) calendar.
Family-told lunar date	Choose lunar, let it convert	The tool maps it to the right solar day and applies solar terms.
Lunar date in a leap month	Choose lunar and mark leap month	Skipping the leap flag can shift the day and your pillars.
Born near a month boundary	Get the date and conversion exact	A solar term can flip the whole month pillar.

What goes wrong when you mix them up

Typing a lunar birthday into a solar field can move your date by roughly a month, because lunar and solar calendars drift apart over the year. That is enough to change your year or month pillar, and with it your Day Master's season, your Five Elements balance and parts of your timing. The chart still looks complete — it just belongs to a different person. This is exactly why two "free saju" sites can hand you two different readings: one converted your calendar correctly and one did not.

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Leap months: the quiet trap

The lunar calendar sometimes inserts an extra leap month to stay aligned with the seasons. If your family gave you a lunar birthday that fell in a leap month and you forget to flag it, the conversion can land a day off — and a day can be enough to change your day pillar, which holds your Day Master. When you enter a lunar date, always note whether it was a leap month.

Born near a boundary? Be extra careful

The most consequential errors happen for people born within a day or two of a solar term. The month pillar does not change on the 1st of the month — it changes at the term. So a birth near the edge can flip the entire month pillar depending on the exact date and conversion. If that is you, getting the calendar right is not a formality; it decides which chart is actually yours.

How to enter your date correctly

STEP 1

Find your solar (Gregorian) date — the one on your passport or birth certificate. If you have it, use it directly.

STEP 2

If you were only told a lunar date, select the lunar option in the calculator instead of typing it as solar.

STEP 3

If that lunar date fell in a leap month, mark the leap-month flag so the conversion lands on the right day.

STEP 4

Let the tool apply the 24 solar terms to set your month pillar, then read your Day Master and Five Elements.

What this guide will not pretend

Getting the calendar right does not make saju a guarantee of any outcome — it simply makes sure the chart you read is genuinely yours. Saju is a centuries-old framework for reflection and self-understanding. The value of this step is honest accuracy: a chart built on the correct date, with leap months and solar terms handled, instead of one quietly built on the wrong day.

Common questions

So the simplest rule is…?

Use your solar (Gregorian) birthday. If you only know a lunar one, choose the lunar option and let the calculator convert it — never type a lunar date into a solar field.

Does the birth time follow the same rule?

Time is a separate question from the calendar. The calendar fixes which day your pillars sit on; the hour fixes your hour pillar. If you are unsure about the time, see the guide to saju without a birth time.

Why do solar terms matter so much here?

Because the month pillar is defined by them, not by the calendar month. A birth near a term can flip the month pillar. Learn how the seasonal calendar works in the 24 solar terms guide.

Where can I see my elements for free?

Right here. The free Cheonmyeongdang calculator lets you pick solar or lunar, handles leap months and solar terms, and turns the correct date into your Day Master and Five Elements in plain English.