How Multifate calculates and checks your chart

BaZi (Four Pillars)

The BaZi calculator turns a birth date and time into four pillars, each made of a heavenly stem and an earthly branch. The calendar arithmetic comes from lunar-javascript, an open-source library under the MIT license. The rules below are the choices our engine applies on top of it.

• The year pillar changes at the exact moment of Li Chun (立春, the Start of Spring), not on 1 January and not at Chinese New Year. In 2024 that moment was 16:27 on 4 February, China Standard Time.
• The month pillar changes at the moment of each of the twelve solar terms that open a month (节), such as Li Chun and Jingzhe (惊蛰). Jingzhe in 2024 fell at 10:22 on 5 March, China Standard Time.
• Both are compared as moments in time. The birth is converted to UTC+8, the zone the solar-term table is written in, and compared with the term to the minute. A fixed UTC+8 is used rather than the Asia/Shanghai time zone, because Asia/Shanghai observed daylight saving from 1986 to 1991.
• The day pillar changes at midnight local time in the birthplace time zone you choose. A birth between 23:00 and 24:00 stays on its own date and falls in the Zi hour, whose hour stem is counted from the next day’s stem.
• Your birth time is read as clock time in that zone, with the zone’s historical UTC offset and daylight saving. True solar time is applied only if you enter a latitude and longitude. It can move the hour pillar, and the day pillar if it crosses midnight (you confirm first), but it never moves the year or month pillar.
• Each branch carries one to three hidden stems: main, middle and residual. In the element tally every visible stem counts 1, and the hidden stems count 0.5, 0.3 and 0.2 in that order.
• If you do not know the birth time, the calculator gives three pillars and no hour pillar. It reads the date at noon in the chosen zone, so on the day of a solar term the year and month pillars can land on the wrong side of the term.
• Luck pillars run in ten-year steps. Their direction follows the yin or yang of the year stem and the gender entered: forward for a yang-year man or a yin-year woman, backward otherwise. The start age counts from birth to the next solar term when going forward and to the previous one when going backward, with three days equal to one year.

The BaZi calculator page works through why two calculators can disagree on the same birth. Related pages: the guides to hidden stems, checking a chart and an unknown birth time, and the luck pillars and ten gods calculators.

Zi Wei Dou Shu

The chart is laid out by iztro, an open-source library under the MIT license, with its default placement of stars, the common version rather than the Zhongzhou variant. The calculator takes a Gregorian date and either a birth time or a two-hour period.

• The Gregorian date is converted to the lunar calendar. The lunar year changes at Chinese New Year, not at Li Chun, so a birth between the two gets one year in Zi Wei Dou Shu and the next in BaZi. At noon on 5 February 2024 the Zi Wei year is 癸卯 (Gui Mao) and the BaZi year is 甲辰 (Jia Chen).
• In a leap month, days 1 to 15 count as the month it repeats and day 16 onward counts as the next month. At noon on 5 April 2023 (day 15 of the leap second month) the Life palace is the You (酉) branch. At noon on 6 April 2023 (day 16) it is the Xu (戌) branch.
• The day turns at midnight, so a birth between 23:00 and 24:00 stays on the date you entered and falls in the first period, Zi.
• The clock time is used as entered. There is no true solar time, birthplace or daylight saving adjustment, so enter the time the clock showed at the birth.
• To find the Life palace, start at the Yin (寅) palace as month 1 and count forward to the lunar birth month. From there count back by the number of the birth period, where Zi is 0, Chou is 1 and so on. Counting forward by the same number gives the Body palace. The stem and branch of the Life palace set the bureau.
• Gender only sets the direction of the ten-year periods (大限): forward through the palaces for a yang-year man or a yin-year woman, backward otherwise. The stars and palaces are the same for both.
• The Four Transformations follow the year stem, using the default table in iztro. Schools disagree on a few stems, so two calculators can differ here and each be consistent with its own table.

See the Zi Wei Dou Shu calculator, the guide to the twelve palaces and the Zi Wei Dou Shu guides.

Da Liu Ren

A Da Liu Ren plate is cast for one minute. You enter the date and time, and the engine builds the heaven and earth plates, the four lessons, the three transmissions and the twelve generals for that minute. The location is not used.

• The day and the hour come from the clock time you type, with no correction for place. The hour branch turns at 23:00, 01:00, 03:00 and so on. The day turns at midnight, so 23:30 belongs to the Zi hour of the same calendar day.
• The month general (月将) changes at the exact moment of the zhongqi (中气, the term in the middle of each month), not at midnight of its date. The minute you type is read in your browser’s time zone and compared with that moment as one point in time. If no zone is sent, the typed clock is read as UTC+8.
• The month general is laid on the hour branch of the earth plate, and the other branches of the heaven plate follow in order. The earth plate does not move.
• The four lessons are read from the day stem, at the palace where it lodges (寄宫), and from the day branch. The first and third lessons take the heaven-plate spirit above the stem’s palace and above the day branch, and the second and fourth each take the spirit above the lesson before.
• The first transmission is chosen by the nine traditional methods in a fixed order, beginning with a lesson in which one spirit overcomes another (贼克). The middle and last transmissions then follow along the heaven plate.
• The nobleman is placed by the day stem and by whether the hour is day or night (the hours from Mao to Shen count as day), and the twelve generals run forward or backward from it.

See the Da Liu Ren calculator and the guides to the month general, the four lessons and the three transmissions.

Meihua

Meihua Yishu builds a hexagram either from three numbers you choose or from the time of the question.

• By numbers: the first number gives the upper trigram and the second the lower, each divided by 8, with a remainder of 0 counted as 8. The third number gives the moving line, divided by 6, with a remainder of 0 counted as 6. The trigrams are numbered 1 Qian, 2 Dui, 3 Li, 4 Zhen, 5 Xun, 6 Kan, 7 Gen, 8 Kun.
• By time: the number of the lunar year branch (Zi is 1, up to Hai as 12), the lunar month and the lunar day are added and divided by 8 for the upper trigram. Adding the number of the hour branch (Zi is 1) and dividing by 8 gives the lower trigram, and dividing the same total by 6 gives the moving line.
• The time is the clock time you enter. The lunar year changes at Chinese New Year, the lunar day at midnight and the hour branch every two hours from 23:00, so only the two-hour period matters, not the minute. A leap month counts under the number of the month it repeats.
• The trigram that holds the moving line is yong (the matter) and the other is ti (the asker). The reading compares their elements: yong generates ti, ti generates yong, they share an element, ti overcomes yong, or yong overcomes ti.
• The mutual hexagram takes lines 2 to 4 and lines 3 to 5, and the changed hexagram flips the moving line.

See the Meihua calculator, the guide to casting with three numbers and the Meihua guides.

Tarot

Tarot is the one system here that is random, so there is no fixed chart to calculate. The engine draws the cards and records what was drawn.

• The deck has 78 cards: 22 major arcana and 56 minor arcana in four suits. The images are the Rider-Waite-Smith deck of 1909, which is in the public domain.
• A draw shuffles the deck with a Fisher-Yates shuffle driven by the platform’s cryptographic random number generator and takes cards from the top, so a card never appears twice in one spread.
• Each card is turned upright or reversed by an independent coin flip.
• A spread is one card, three cards (past, present, future) or five cards. The position of each card is recorded with it.
• What a card means comes from a fixed table with an upright and a reversed meaning for every card, so the same card in the same orientation always carries the same words.
• Asking again draws again. Unlike the four calculated systems, the same question does not give the same cards.

See the Tarot reader and the guide to reading a three-card spread.

How the calculations are checked

The four calculated systems are deterministic, so a check compares the engine’s output with a recorded answer. The checks run on every change, and a release goes out only when all of them pass.

• BaZi: tests compare the year and month pillars with solar-term moments across time zones (04:30 on 4 February 2026 is before Li Chun in Seoul and after it in Shanghai). A fixed 1984 chart is held as a reference, and charts on 182 dates from 1930 to 2007, covering all twelve hours, each for a man and a woman (364 charts), are built, and the rule readings made from them are fingerprinted, so a change that reaches a reading is noticed and reviewed.
• Zi Wei Dou Shu: a fixed reference chart, and a grid of 81 charts: 69 dates from 1930 to 2005 covering all twelve hours, with men and women alternating, plus 12 births of 2026.
• Da Liu Ren: a grid of 8,640 plates, one for every combination of the 60 day pillars, 12 hours and 12 month generals. Three-transmission test cases from an open-source table (liuren-ts-lib), worked examples from the classic Liu Ren Da Quan (六壬大全) and the nobleman placement from a patent description (CN1218923A) are compared with the engine. The month general switch at Yushui 2026 is tested to the minute in Beijing and Tokyo time.
• Meihua: all 64 main hexagrams, with no line moving, each single line moving and several lines moving, read under each casting method, plus fixed number and time casts checked against the arithmetic.
• Tarot: every card is checked to have its image and both meanings, every card is read upright and reversed on its own, and cards rotate through every position of the three- and five-card spreads with every mix of orientations.
• Time zones: BaZi and Zi Wei Dou Shu charts are built again with the computer set to five different time zones, including zones that skip or repeat an hour for daylight saving, and each chart must equal the one made under UTC.

The solar-term moments come from the lunar-javascript tables and the star placement from iztro, so the accuracy of those two sources is part of ours. These checks show that the engine does what this page says and that it does not change by accident. They do not show that one school’s rules are the only correct ones.

Calculation versions

The current calculation version is v13. The version is saved with each chart, so a chart can be traced to the rules that made it.

• 20 October 2026, v13: the Da Liu Ren month general now changes at the exact moment of the zhongqi, using the time zone of the reader, instead of by calendar date. A cast within hours of a zhongqi can have a different month general than before.
• 18 October 2026, v12: the BaZi year and month pillars now compare the birth moment with the solar terms after converting it to UTC+8, and the luck pillar start follows the same frame. The day and hour pillars, true solar time and the Zi hour rule did not change.

If you find a calculation error

Write to support@multifate.com or use the contact page. Please include the birth date and time, the time zone, the page you used, the version shown in the receipt, the result you got, and the result you expected with its source (a book, an almanac or another calculator).

We run the same input through the engine and reply with the rule that explains the difference. If the rule is wrong, we correct it and record the change in the version history above.

What a calculation cannot tell you

A calculation answers one question: given this input and these rules, which chart follows. It does not say what the chart means or what will happen. Interpretation differs by school and by reader, and agreement between two readings is not independent proof of a prediction.

Schools also differ on the calculation itself: where the day turns, how the Zi hour at 23:00 is counted, whether the year turns at Li Chun or Chinese New Year, which table gives the Four Transformations, and how a Da Liu Ren plate chooses its first transmission. This page states the choice we make for each, so you can compare it with another calculator. We do not claim that one choice is the only correct one.

A birth time that is off by a few minutes can change a pillar or a palace, especially near midnight, near a solar term or at the edge of a two-hour period. AI readings interpret a chart and can be wrong. Multifate is for entertainment and reflection and gives no medical, legal or investment advice. See the Terms of Service.