A data da Hégira costuma ser calculada de formas diferentes por diversos autores.
A chegada de Maomé a [[Iatrebe]] (Medina) ocorreu no dia 12 do antigo mês ''RabiaRabinia'', que corresponde a [[24 de setembro]] de [[622]] pelo [[calendário juliano]], e sua fuga de Meca no dia 1 do mês ''Rabia''.<ref name="dictionary.p.158">''A New and General Biographical Dictionary: Containing an Historical and Critical Account of the Lives and Writings of the Most Eminent Persons in Every Nation, Particularly the British and Irish, from the Earliest Accounts of Time to the Present Period : Wherein Their Remarkable Actions Or Sufferings, Their Virtues, Parts, and Learning are Accurately Displayed : with a Catalogue of Their Literary Productions, Volume 8'' (1762), ''Mahomet'', p.158 [http://books.google.com.br/books?id=IrEDAAAAYAAJ&pg=PA158&f=false <nowiki>[google books]</nowiki>]</ref> [[John Bruno Hare]] calcula da data da fuga de MecaMejca em [[20 de setembro]] de [[622]].<ref name="j.b.hare.islamic.date" />
