Saju Calculation Method, Example, and Limits
See the exact Four Pillars calculation pipeline, a reproducible example, visible-element percentage method, and known boundary limitations.
External reference check: ten lunar dates
The first days of January–October match the HKO 2026 lunar date table. These samples check lunar conversion only, not Saju pillars, historical timezones, or personality interpretations.
HKO 2026 source PDF · 2026-09-05
| Gregorian | Reference month/day | Engine month/day |
|---|---|---|
| 2026-01-01 | 11/13 | 11/13 |
| 2026-02-01 | 12/14 | 12/14 |
| 2026-03-01 | 1/13 | 1/13 |
| 2026-04-01 | 2/14 | 2/14 |
| 2026-05-01 | 3/15 | 3/15 |
| 2026-06-01 | 4/16 | 4/16 |
| 2026-07-01 | 5/17 | 5/17 |
| 2026-08-01 | 6/19 | 6/19 |
| 2026-09-01 | 7/20 | 7/20 |
| 2026-10-01 | 8/21 | 8/21 |
Birth-hour comparison
Enable JavaScript to compare two hours interactively. On 2000-01-01, 22:00 gives Hour 癸亥 and 23:00 gives 甲子; both retain Day 戊午. An unknown hour omits the Hour Pillar and counts six visible characters. This demonstrates one engine, not independent accuracy certification.
What the calculator does
The tool converts a supplied Gregorian birth date and optional whole-hour local time into Year, Month, Day, and Hour stem-branch pairs. It displays those values, identifies the Day Master from the Day Stem, and counts the primary element assigned to each visible stem and branch.
What it does not calculate
Birthplace, historical timezone, daylight-saving correction, longitude, true solar time, hidden stems, seasonal weighting, combinations, clashes, ten gods, and favorable-element systems are outside the current model. Weekly prose is cultural and entertainment-oriented interpretation rather than a scientifically validated prediction.
Input and boundary assumptions
The form accepts a Gregorian date and blocks impossible dates. When time is omitted, noon is a provisional internal value and the Hour Pillar remains unavailable. Near a solar-term transition, an unknown hour can also leave the Year or Month Pillar uncertain. Borderline births need independent verification.
Calculation pipeline
The calendar engine derives the Eight Characters from the solar date. Each visible Heavenly Stem and Earthly Branch receives one primary element label. Six or eight visible units are counted and a largest-remainder calculation keeps the percentages at exactly 100%. Hidden stems and seasonal strength are not included.
Reproducible example
For 1 January 2000 at 12:00 local time the current engine returns Year 己卯, Month 丙子, Day 戊午, and Hour 戊午. The visible elements are Earth 38%, Fire 38%, Wood 12%, Water 12%, and Metal 0%. This is a transparent count, not a claim that a person is a percentage of an element.
How to audit a report
Save the original date, calendar system, local time, birthplace, and source record. Compare the stem-branch pairs with an independent calendar source, count the visible elements, and separate each narrative sentence into calculation, traditional interpretation, or practical suggestion.