Compare charts without guessing
Why do two Saju calculators disagree?
If the same birthday produces different Four Pillars, start with the inputs and calculation rules. A difference does not, by itself, tell you which chart is “right.”
It is easy to compare the large personality labels on two result pages and miss the underlying cause. Compare the four pairs of stem and branch characters first. If the pillars match but the readings differ, the issue is interpretation rather than calculation. If a pillar differs, work through the checks below in order.
Check the character pairs in your chart
Calculate your chart here, then compare the Year, Month, Day and Hour pairs with the other result. This checks our published rules; it does not certify another calculator as right or wrong.
First: are the birth details actually identical?
Confirm the date was entered in the same calendar, the clock time uses the same a.m./p.m. convention, and both sites use the time zone at the place and date of birth. “11:30” and “23:30” are twelve hours apart. A time zone also may have had a different daylight-saving rule in the birth year than it has today. If you do not know your birth hour, compare only the pillars that remain stable across plausible times instead of letting a calculator fill the hour with an unexplained default.
Second: compare the boundary rules
| Question | Why it matters | Hello Saju's current choice |
|---|---|---|
| When does a day change? | A late-night birth may be assigned to a different day pillar. | The day boundary is midnight (00:00), not 23:00. |
| What sets the year and month pillars? | Solar-term boundaries need not coincide with the first day of a civil month or Lunar New Year. | The calculation engine uses the solar-term calendar. |
| Is clock time adjusted for longitude? | A birth near a two-hour boundary may move to a neighboring hour pillar. | True-solar-time correction is enabled with the configured country longitude. |
| How precise is the birthplace? | A country may span more than one time zone or many degrees of longitude. | One main time zone and one representative coordinate per supported country; no city-level selection. |
These rules matter most near a boundary. For a birth well away from midnight, a solar term and an hour transition, the same inputs often produce the same pillars even when the services describe them differently. Do not infer that a difference in an element chart always means the birth-day stem changed.
Third: check what the element graphic counts
Hello Saju's visible five-element tally counts the primary elemental association of each of the four stems and four branches. It does not weight hidden stems, seasonal strength or every relationship in the chart. Another site may use a weighted “strength” score and show different proportions while agreeing on all eight characters. These displays answer different questions. Your Day Master is the day stem, not whichever element bar is tallest.
What if your birth time is approximate or unknown?
For an approximate time, Hello Saju checks up to seven times within ninety minutes either side of the time entered, keeping them on the same civil date. For a fully unknown time, the paid reading checks twenty-four hourly candidates. The free snapshot and free two-person comparison use three date-boundary checks, at 00:00, 12:00 and 23:59, and leave the hour unassigned. Neither is a search through every possible minute. The birth-time guide explains what to do when the result remains uncertain.
A five-minute comparison checklist
- Put the two charts side by side and note which pillar characters differ: year, month, day or hour.
- Re-enter the same civil date, clock time and a.m./p.m. choice. Check whether one site expects a lunar date.
- Check the birth location, historical time zone and daylight-saving setting. Hello Saju only accepts country-level locations.
- If the day differs and the birth was late at night, compare the day-boundary policy. If the month or year differs near a solar term, compare the calendar convention.
- If only the hour differs, compare place precision and true-solar-time settings. If all pillars match, compare the interpretation method instead.
If the birth was close to a boundary, or the country has several time zones, use a city-specific calculation with the historical civil time. Our country selection may be too broad to settle the difference.
See your free Day Master snapshot →
Method and editorial note
This guide describes the calculation choices implemented in Hello Saju's current engine and input form. For the complete method, see How the Four Pillars Are Calculated. For the cultural definition of the Four Pillars, see the Encyclopedia of Korean Culture's Saju entry. We do not claim that any chart scientifically predicts events. Questions or corrections: [email protected].