Convert Tropical Years to Months
Convert Tropical Years (a_trop) to Months (mo) instantly and accurately.
Conversion Formula
mo = a_trop × 11.99998981
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 Months
A mean Gregorian calendar month = 365.2425 ÷ 12 = 30.436875 days = 2,629,746 s exactly (averaged over the 400-year cycle with exactly 97 leap years). Individual months have 28-31 days. Loan schedules, subscriptions, and mobile billing reference 'per month', requiring explicit agreement on meaning. ISO 8601 uses 'P1M'. 1 mo = 30.436875 d = 2,629,746 s.
Quick Reference Table
| Tropical Years (a_trop) | Months (mo) |
|---|---|
| 1 a_trop | 12 mo |
| 2 a_trop | 24 mo |
| 5 a_trop | 59.9999 mo |
| 10 a_trop | 120 mo |
| 25 a_trop | 300 mo |
| 50 a_trop | 599.999 mo |
| 100 a_trop | 1200 mo |