Convert Sidereal Months to Gregorian Years
Convert Sidereal Months (sid.mo) to Gregorian Years (yr) instantly and accurately.
Conversion Formula
yr = sid.mo × 0.07480416898
About Sidereal Months
The sidereal month = Moon's orbital period relative to the fixed stars = 27.3217 days = 2,360,591.6 s - the shortest lunar month. It is ~2.21 days shorter than the synodic month (29.53 d) because Earth advances ~27° along its orbit in the same period; the Moon must travel further to re-align with the Sun. Used in GPS orbit design, tidal modelling, and lunar laser ranging. 1 sid.mo = 27.3217 d.
About Gregorian Years
The Gregorian year = exactly 365.2425 days = 31,556,952 s (mean over the 400-year cycle with 97 leap years). The Julian calendar (45 BCE) used 365.25 days; Gregorian reform (1582) dropped 10 days and amended the centennial rule. Britain adopted it in 1752; Greece in 1923. Carbon-14 dates are reported in 'years BP' (before 1950 CE). 1 yr = 365.2425 d = 8,765.82 h = 31,556,952 s.
Quick Reference Table
| Sidereal Months (sid.mo) | Gregorian Years (yr) |
|---|---|
| 1 sid.mo | 0.0748042 yr |
| 2 sid.mo | 0.149608 yr |
| 5 sid.mo | 0.374021 yr |
| 10 sid.mo | 0.748042 yr |
| 25 sid.mo | 1.8701 yr |
| 50 sid.mo | 3.74021 yr |
| 100 sid.mo | 7.48042 yr |