Convert Gregorian Years to Seconds
Convert Gregorian Years (yr) to Seconds (s) instantly and accurately.
Conversion Formula
s = yr × 31556952
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.
About Seconds
The second (s) is the SI base unit of time, defined since 1967 as exactly 9,192,631,770 periods of the caesium-133 ground-state hyperfine transition at 0 K. Caesium fountain clocks realise this to ~10⁻¹⁶ (1 s lost per ~300 million years); optical lattice clocks (Sr, Yb) reach ~10⁻¹⁸. The second links to the metre via the defined speed of light c = 299,792,458 m/s exactly. 1 s = 1,000 ms = 1/60 min.
Quick Reference Table
| Gregorian Years (yr) | Seconds (s) |
|---|---|
| 1 yr | 31557000 s |
| 2 yr | 63113900 s |
| 5 yr | 157785000 s |
| 10 yr | 315570000 s |
| 25 yr | 788924000 s |
| 50 yr | 1.578 × 109 s |
| 100 yr | 3.156 × 109 s |