Tools
Free online tool

Choosing a year to build or break ground

Scores 19 factors from the owner’s age and the building’s orientation — Kim Lau, Hoang Oc, San Tai, and the year’s mountain-and-facing rules — then lists the years that come out clear.

The three age factors everyone asks about

All three are computed from the owner’s nominal age (age counted from one at birth):

FactorMethodSaid to affect
Kim LauThe remainder of the nominal ageThe owner, spouse, children or livestock — depending on the remainder
Hoang OcSix palaces, some favourable, some notThe fortune of the house and those living in it
San TaiThree consecutive years by trine groupStarting major undertakings

Classical practice checks all three together, never one alone. The tool shows each factor with its reasoning so you can see why a year was excluded.

Building new and renovating are judged differently

  • New build — all 19 factors apply, including the three age factors above.
  • Renovation — the age factors are waived; only the year and orientation factors remain. This distinction between founding something new and repairing something existing is standard.

If you have measured the facing bearing (0–360°), enter it: the tool converts it to a sitting–facing pair among the 24 mountains and adds the year’s orientation rules.

After you have a year

This tool stops at the year, because age and year are the heaviest filters — once a clear year is fixed, finding a month and day is comparatively easy.

Next step: use the Chinese almanac to choose the day for breaking ground, raising the ridge beam and moving in; and the feng shui tool for the house itself.

Read more

Frequently asked questions

Can I borrow someone else’s age to build?
That is a common custom when the owner’s year is unfavourable: someone with a suitable age formally breaks ground. The tool does not model the borrowing itself, but you can enter that person’s birth year to check whether the year is clear for them.
How do I enter the facing direction?
As a compass bearing from 0 to 360 degrees, measured in the direction the front of the house looks out. If you cannot measure it yet, leave it blank and review the age and year factors first.
How is Hoang Oc different from Kim Lau?
Both use the nominal age but by different methods and with different meanings. Kim Lau divides by remainder and points at a person; Hoang Oc sorts into six palaces describing the fortune of the dwelling. They are meant to be read together.
Is renovation really exempt?
By common practice, yes — repairing is treated more lightly than founding. Families differ, so if yours observes the stricter form, use the new-build setting.