Convert Tropical Years to Gregorian Years
Convert Tropical Years (a_trop) to Gregorian Years (yr) instantly and accurately.
Conversion Formula
yr = a_trop × 0.9999991512
About Tropical Years
The tropical year = time from March equinox to the next = 365.24219 days = 31,556,925.2 s - the year that governs the seasons. The Gregorian 97/400 leap rule approximates it as 365.2425 days, leaving a residual drift of only ~26.8 s/year. The tropical year shortens ~0.53 s per century due to tidal deceleration. Persian Solar Hijri and Mayan Haab' calendars also approximate it. 1 a_trop ≈ 365.24219 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
| Tropical Years (a_trop) | Gregorian Years (yr) |
|---|---|
| 1 a_trop | 0.999999 yr |
| 2 a_trop | 2 yr |
| 5 a_trop | 5 yr |
| 10 a_trop | 9.99999 yr |
| 25 a_trop | 25 yr |
| 50 a_trop | 50 yr |
| 100 a_trop | 99.9999 yr |