Tool · BaZi basics
Day Master Calculator (日主)
Your day master, 日主, is the heavenly stem of your day pillar. It is the one character every BaZi reading is measured against: your element balance is asked about it, and every other character in the chart is named by its relationship to it. Enter a birth date and the calculator will find yours — the date alone is enough.
The short version
The day master is not a star sign and not a personality type. It is the reference point of a chart — the “self” that everything else is described relative to.
You do not need your birth time to find it. The day pillar changes at midnight, not at an hour boundary, so the date by itself gives the correct answer for almost every birth.
Your day master
Free · no sign-up
The time field can be left unknown here and the day master will still be exact. The one edge case — a birth between 23:00 and 23:59 — is explained below.
How it’s calculated
- 1
Take the day pillar
The day pillar is one of the four 干支 pairs in the chart, and it advances exactly one step per calendar day with no gaps. That continuous count is what makes it reliable: it does not depend on the calendar reform, the timezone, or the season.
- 2
Read its heavenly stem
The stem of that pair is the day master. 庚子 means the day master is 庚 — yang metal. The branch below it describes the ground the day master stands on, but the day master itself is only the stem.
- 3
Set it as the reference
From here everything else in the chart is classified relative to this one character: the ten gods by relationship, the element balance by whether each element supports or drains it.
The full rule set — every convention, in order, with the engine field names — is published on the methodology page.
What the day master actually is
A BaZi chart contains four stems and four branches, but only one of those characters is the subject. That is the day stem — the day master. It is not “your strongest element” or “your ruling planet”; it is simply the pivot the rest of the chart is described around. Reading a chart without fixing the day master first is like describing a journey without deciding where it started.
Because it is the pivot, the day master is what the element balance is about. Our five-element tally counts support and drain relative to the day master’s element, and that is the only reason “support” and “drain” mean anything. Ten percent Fire is neither good nor bad in the abstract; it depends on whether the day master is Fire.
It is also the reason the ten gods exist. Companion, Output, Wealth, Officer and Resource are five ways another character can stand relative to the day master. Change the day master and all eight characters change their names, even though the characters themselves have not moved.
You do not need your birth time for this
Most calculators ask for a birth time because the hour pillar needs one — and many people do not know theirs, which is a real and common limit. The day master is the part that survives it. The day pillar changes at midnight, not at an hour boundary, so a birth at any time between 00:00 and 22:59 on a given date has the same day master.
When the time is unknown, this engine anchors the calculation at local noon and returns a three-pillar chart — year, month and day. The day master is exact. What you lose is the hour pillar: the ten-god relationships that only the hour column can supply, and some precision in the start age of the luck pillars. Both limits are stated on the result rather than hidden.
There is one genuine edge case. A birth between 23:00 and 23:59 belongs to the next day’s 子 hour, while the day pillar itself stays on the current date. If your birth was in that hour, the hour column is affected and the day master is not — but you should know the difference exists, which is why we name it here.
The ten day masters, and what they are not
There are ten day masters, one per heavenly stem, and the profiles are below. They are classical images rather than personality results: 甲 is the tall tree, 壬 is the ocean, 辛 is the jewel, 癸 is the rain. The image is a shorthand for the qualities the tradition associates with that element and polarity.
What these profiles are not is a diagnostic. Two people with 庚 yang metal as their day master can have entirely different charts, because the day master is one character out of eight. The element and polarity are the starting material; what the chart does with that material is the reading.
So read your profile as a description of a starting point, not a conclusion. If it does not fit, that is useful information rather than a contradiction — it usually means the rest of the chart is doing something more interesting than the day master alone suggests.
Strong, weak, and why we do not score it
Classical BaZi spends a great deal of effort deciding whether a day master is “strong” or “weak” — that is, whether the chart supplies more support than it drains. This is a real and important judgement, and the answer changes how every other element in the chart is read.
It is also the point where published systems diverge most, because “strong enough” depends on how you weight the month you were born in, whether hidden stems count fully, and whether rootedness matters more than raw count. Three competent readers can disagree.
We therefore do not print a strength score. We print the raw support and drain counts, tell you they are unweighted, and leave the judgement where it belongs — with the reading, not with the calculator. If a site gives you a single number out of 100 for this, ask it which of the three weightings it used.
A worked example
The worked case used across the site: 4 February 1990, Taipei. The day master depends only on the date, so this is reproducible with or without a birth time.
Input
- Date
- 4 Feb 1990
- Time
- 10:00
- Place
- Taipei, Taiwan
- Time zone
- Asia/Taipei
Nearest 节
Next: 立春, 4 Feb 1990 10:14Birth at 10:00 — 14 minutes before the year boundary.
Day master
庚 — Yang Metal
Image: the blade · from the day pillar 庚子
- Day pillar
- 庚子
- 纳音 壁上土
- Needs only the date
- No birth time required
- the day changes at midnight, not at an hour boundary
The day pillar 庚子 is the anchor of the whole chart. 己 (year stem) becomes Direct Seal — a resource feeding the metal. 丁 (month stem) becomes Direct Officer — fire that controls it. 辛 (hour stem) is Rob Wealth, a peer of the same element at the opposite polarity.
One character, and eight names changed
The day pillar is 庚子, so the day master is 庚 — yang metal. Everything else on this page follows from that single fact. 己 in the year pillar is Earth, which generates metal, so it becomes Direct Seal. 丁 in the month pillar is Fire, which controls metal, so it becomes Direct Officer. 辛 in the hour pillar is metal at the opposite polarity, so it becomes Rob Wealth. Change 庚 to 甲 and all three of those names change, even though the other three characters have not moved at all.
Engine v1.1.0 · these eight characters, this tally — reproduce them any time from the same input.
The ten day masters
One per heavenly stem. The element and polarity are the starting point; what makes a chart specific is what the rest of it does with that starting point. Each one has its own page — open it for the full profile, the ten-god map read from that stem, and a reproducible chart.
- 甲
Yang Wood
Jiǎ · 木 · image: the tall tree
Growth with a direction. Yang Wood is read as principle and long-term structure — it tends to grow through an obstacle rather than around it.
Yang Wood day master - 乙
Yin Wood
Yǐ · 木 · image: the vine
Growth by adaptation. Yin Wood is read as resilience and relationship — it survives by finding the route that is already there.
Yin Wood day master - 丙
Yang Fire
Bǐng · 火 · image: the sun
Light without a target. Yang Fire is the most outwardly visible of the ten — read as expression, warmth and reach.
Yang Fire day master - 丁
Yin Fire
Dīng · 火 · image: the lamp
Light with intent. Yin Fire concentrates on one thing at a time — read as focus, selective warmth and quiet intensity.
Yin Fire day master - 戊
Yang Earth
Wù · 土 · image: the mountain
Mass and stability. Yang Earth is what things get built on — read as reliability, endurance and holding ground.
Yang Earth day master - 己
Yin Earth
Jǐ · 土 · image: the field
The soil in the pot. Yin Earth is the most accommodating of the ten — read as cultivation, patience and giving things conditions to grow.
Yin Earth day master - 庚
Yang Metal— this is yours
Gēng · 金 · image: the blade
Material that becomes useful by being worked. Yang Metal is read as directness, decisiveness and a low tolerance for ambiguity.
Yang Metal day master - 辛
Yin Metal
Xīn · 金 · image: the jewel
Precision and finish. Yin Metal is valued for quality rather than force — read as refinement, standards and discernment.
Yin Metal day master - 壬
Yang Water
Rén · 水 · image: the ocean
The largest thing in the chart by volume. Yang Water moves constantly and takes the shape of its container — read as range and adaptability.
Yang Water day master - 癸
Yin Water
Guǐ · 水 · image: the rain
Arrives quietly and gets into everything. Yin Water nourishes without announcing itself — read as subtlety and persistence through softness.
Yin Water day master
These are classical images, not personality test results. A day master describes the starting material of a chart; two people with the same 庚 day master can read very differently once the other seven characters are in play.
Questions
- How do I find my day master?
- Enter your birth date above — that is the only field required to be accurate. The day master is the heavenly stem of your day pillar, and the day pillar advances one step per calendar day, so any date resolves to exactly one day master regardless of the time you were born.
- Can I find my day master without a birth time?
- Yes, and it will be exact. The day pillar changes at midnight rather than at an hour boundary, so a birth anywhere between 00:00 and 22:59 on a given date gives the same day master. Only births between 23:00 and 23:59 need care, because that hour belongs to the next day’s 子 hour while the day pillar stays on the current date.
- Is the day master the most important part of my chart?
- It is the most load-bearing — not the same thing. Its role is to be the reference point: the element balance is asked about it, and every other stem is named by its relationship to it. That makes it the first thing to establish, but the reading still depends on all eight characters.
- What if I do not identify with my day master profile?
- That is expected more often than not. The profile describes one character out of eight — the starting material, not the outcome. A chart is read by combining the day master with the element balance, the ten gods and the luck pillars; the day master alone is a shorthand, and the tradition treats it as such.
Next
Five elements calculator
See what supports and drains your day master, counted from all eight characters.
OpenTen gods calculator
Every character in your chart named by its relationship to the day master.
OpenGuide: BaZi without a birth time
Exactly what survives when the hour pillar is unknown — and the one hour of the day that changes the answer.
OpenFull chart
Get your own four pillars
The calculator is free and needs no account. It shows all four pillars, hidden stems, ten gods, your element balance and ten-year luck cycles — with the engine version on the result.
BaziPattern provides AI-generated readings for entertainment and cultural exploration purposes only. Readings are not predictions, or medical, legal, or financial advice.