Khums is an Islamic income tax, which is 1/5 (20%) of the remaining of yearly income, after all legitimate expenses have been paid.
The remaining sum after the 20% reduction does not have to be taxed again for the following years if it has not been used.
The amount of tax paid must be given to the Marja’ (jurist) through his offices or representatives (who are authorized in writing), to be distributed, under the supervision of Marji’ for the sake of educating, building and promoting the Muslim community and teaching the true message of Islam in general (i.e. helping the poor and needy, building or contributing toward hawzahs (seminaries, supporting clergy, Islamic centers, Islamic schools, etc.)
IMAM accepts khums to use for purposes mentioned above in the United States. For larger khums amounts, it is recommend to submit your khums payment by mail by personal or cashiers check, to avoid credit card fees, which I.M.A.M. covers through non-khums funding.
To read more about the jurisprudence details of khums click here.