Shenshahi and Kadmi are perpetual 365-day reckonings — twelve Mah of thirty Roj followed by five Gatha days, with no leap-day correction, which is why they drift against the seasons. Kadmi runs exactly one intercalary month ahead of Shenshahi. Fasli is the reformed solar calendar adopted in 1906: Navroz is pinned to 21 March and a sixth Gatha day is inserted before a Gregorian leap year, so it never drifts. All conversions here are computed in your browser, in your local time.