Convert Julian Years to Days

Convert Julian Years (a_J) to Days (d) instantly and accurately.

Julian Years (a_J)
Days (d)

Conversion Formula

d = a_J × 365.25

About Julian Years

The Julian year (a_J) = exactly 365.25 days = 31,557,600 s - the IAU standard year for astronomical distances. The light-year is formally 1 ly = c × 1 a_J = 9.461 × 10¹⁵ m (IAU 2012 B2). Julian years differ from Gregorian years by only 648 s (~10.8 min/year); important for high-precision astrometry or calculations spanning centuries. 1 a_J = 365.25 d = 31,557,600 s.

About Days

A day (d) = exactly 86,400 s. Earth's actual solar day varies ±16 s due to orbital eccentricity and axial tilt (equation of time). Leap seconds (abandoned in UTC after 2035) corrected the TAI-UT1 divergence. Mars's sol = 24 h 39 min 35 s ≈ 88,775 s; a Martian year = 668.6 sols. The day structures circadian biology, tides, and planetary science. 1 day = 86,400 s = 24 h.

Quick Reference Table

Julian Years (a_J)Days (d)
1 a_J365.25 d
2 a_J730.5 d
5 a_J1826.25 d
10 a_J3652.5 d
25 a_J9131.25 d
50 a_J18262.5 d
100 a_J36525 d

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