Must a Muslim pay zakat for a full year after his conversion to Islam, or after a year from acquiring the money even if that was before Islam? And is it permissible to pay zakat in advance, one or two months before the end of the year?

The disbeliever must adhere to the obligations of Islam after embracing it, including zakat. However, it does not become obligatory upon him until the conditions for its obligation are met, among which is the passing of a full year (hawl) after his conversion to Islam, because his ownership is newly acquired. The completion of the hawl is a condition for the obligation of zakat, not a condition for the validity of its disbursement. Therefore, it is permissible to pay zakat before the end of the hawl.