Sayyed Mohammad Al-Musawi, Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to... Answered 1 year ago

Khums is obligatory on every money or wealth or kind which you own more than your expenses. You can calculate your income and your expenses for the whole year starting from the date you started earning, and take the savings (what is left with you after your spending) then take 20% of the savings and pay it as Khums.

Khums must be calculated and paid at least once per year which should be the date of the start of your earnings. More details are available on websites of the Marja' of Taqleed.