Why it exists
People who discover Saju through Korean dramas, music and friends usually ask the same thing next: “how do I read mine?” AI assistants can give a surprisingly good reading, but only if the chart they start from is correct, and they are poor at calculating it themselves. SajuPaste does the calculation properly and hands you text that any assistant understands. No account, no fee, nothing stored.
Who makes it
SajuPaste is made in Korea by choisaju, who also runs Korea Fortune, a Saju reading service in English. You can find choisaju on Threads and Instagram under the same name. The calculation engine is shared between the two sites.
How the chart is calculated
- Year and Month pillars use the exact solar-term boundaries for the birth moment, not calendar months.
- Day and Hour pillars use true solar time at the birthplace: the clock time is corrected by the longitude of the city and the equation of time.
- Time zones and daylight-saving rules are taken from the IANA time-zone database, so births during Korea’s 1987–88 summer time, the UTC+8:30 era, or a US daylight-saving change are handled automatically.
- Lunar birthdays are converted to the solar calendar, including leap months.
- The engine is based on ssaju, an open-source Four Pillars library (MIT licence), extended with the global time handling above. City data comes from GeoNames (CC BY 4.0).
What the site does with your data
Your birth data is sent to the server once to compute the chart and is not written anywhere. The result is returned to your browser and kept only there, so that the form survives moving between pages. Share links contain the inputs in the address itself; nothing is looked up on our side when someone opens one. What you paste into an AI assistant is governed by that assistant’s privacy terms.
What it deliberately leaves out
SajuPaste calculates the natal chart and includes only the current ten-year luck pillar. The full luck cycles, the year ahead, compatibility and date selection are readings rather than calculations, and they live on Korea Fortune.