Although there are no official statistics of Muslims in Sweden, estimates counts 200 000—250 000 ethnic Muslims in 2000 (i.e. anyone who fits the broad definition of someone who "belongs to a Muslim people by birth, has Muslim origin, has a name that belongs in the Muslim tradition, etc. "), roughly estimated close to 100 000 of which are of second-generation. Of the first-generation Muslims, 255 000 are thought to be Sunni, 5 000 Shi’ites, no more than 1 000 Ahmadiya, Alevi and other groups and probably no more than 5 000 converts – mainly women married to Muslim men. In 2009 a US report made a statement that there are 450 000 to 500 000 Muslims in Sweden, around 5% of the total population, and that the Muslim Council of Sweden reported 106 327 officially registered members. Swedish estimates are rather 350 000, including nominal Muslims and people from a Muslim background.
Such numbers do not imply religious beliefs or participation; Åke Sander claimed in 1992 that at most "40–50% of the ethnic Muslims in Sweden could reasonably be considered to be religious", and in 2004, based on discussions and interviews with Muslim leaders, concerning second-generation Muslims born and raised in Sweden that "it does not seem that the percentage they consider to be religious Muslims in a more qualified sense exceeds fifteen percent, or perhaps even less". Sander re-stated in 2004 that "we do not think it unreasonable to put the figure of religious Muslims in Sweden at the time of writing at close to 150 000". Prof. Mohammad Fazlhashemi at Umeå University counts with "a good 100 000". About 25 000 are regarded as devout Muslims, visiting Friday prayers and practising daily prayers.