Why is Naw-Rúz astronomically determined instead of a fixed date?

Per the Universal House of Justice's 2014 ruling (effective 2015), Naw-Rúz is the day of the actual astronomical vernal equinox as observed at the Tehran meridian, rather than a fixed Gregorian calendar date — a genuine, real astronomical anchor, not an approximation.

Why does this calculator sometimes show uncertainty about the exact date?

In years where the equinox falls very close to Tehran sunset, a small difference in exactly how "Tehran sunset" or the equinox moment is computed can shift the result by a day — an honest limitation, disclosed via a caution banner, rather than asserting false precision.

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Baháʼí Tools

Badí Calendar Converter

Convert between the Gregorian and Badí (Baháʼí) calendars.

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About the Badí Calendar Converter

Converts dates between the Gregorian calendar and the Badí (Baháʼí) calendar, in either direction.

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How to use it

Choose a direction: Gregorian to Badí, or Badí to Gregorian.
Enter the date.
Read the converted date.

Formula

The Badí calendar has 19 months of 19 days each (361 days), plus 4 or 5 intercalary Ayyám-i-Há days inserted before the final month (ʻAláʼ) to stay aligned with the solar year. Naw-Rúz (New Year, 1 Bahá) is anchored to the real astronomical spring equinox at the Tehran meridian, per the Universal House of Justice's 2014 ruling — not a fixed calendar date.

Worked example

Naw-Rúz 2026 (183 B.E.) falls on March 20 or 21 by this calculation — a genuinely uncertain year (see note); 2024, 2025, and 2027 all computed with a comfortable margin and matched published dates exactly.

Interpreting your result

Some years are genuinely uncertain: when the equinox falls within minutes of Tehran sunset, this calculation's result can differ by a day from the officially-announced date, since the exact reference method (coordinates, refraction convention) bahai.org uses isn't fully disclosed. A caution banner appears automatically for any such year — always confirm against bahai.org's own official calendar when it does.

Recommendations

• Year 1 B.E. (Baháʼí Era) began at Naw-Rúz 1844 CE, the year of the Báb's declaration.

Frequently asked questions

It's the calendar structure established by the Báb and confirmed by Bahá'u'lláh — 19 x 19 = 361 days, with intercalary Ayyám-i-Há days added to keep the year aligned with the solar year, similar in purpose to a leap day.