Convert Days to Julian Years
Convert Days (d) to Julian Years (a_J) instantly and accurately.
Conversion Formula
a_J = d × 0.002737850787
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.
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.
Quick Reference Table
| Days (d) | Julian Years (a_J) |
|---|---|
| 1 d | 0.00273785 a_J |
| 2 d | 0.0054757 a_J |
| 5 d | 0.0136893 a_J |
| 10 d | 0.0273785 a_J |
| 25 d | 0.0684463 a_J |
| 50 d | 0.136893 a_J |
| 100 d | 0.273785 a_J |