It is the obligation of zakat for people who have income from other than those previously mentioned, such as doctors, drivers, private employees, civil servants, teachers, brokers, and so on. So their obligation to pay zakat is 2.5% of the gross income earned. According to Yusuf Qardhawi, the calculation of professional zakat is distinguished according to two ways:
1. Directly, zakat is calculated from 2.5% of gross income directly, whether paid monthly or annually. This method is more appropriate and fair for those who are generously provided for by Allah.
Example: A person with an income of IDR 3,000,000 per month is obliged to pay zakat in the amount of: 2.5% X 3,000,000 = IDR 75,000 per month or IDR 900,000 per year.
2. After deducting basic needs, zakat is calculated as 2.5% of the salary. This method is fairer for those whose income is modest.
Example: A person with an income of IDR 1,500,000 and expenses for basic needs of IDR 1,000,000 per month is obliged to pay zakat: 2.5% X (1,500,000-1,000,000) = IDR 12,500 per month or IDR 150,000 per year.
In the madhhab of Ahl al-Bayt, this obligation is called khums. It is an obligation to spend 20% of the net income at the end of the year, which is determined by each person according to when he started his business or received his salary.
So, if a person starts his business/job on April 1, then every March 31 he has to calculate the balance of his business. This is the remainder of his income after spending on his needs. It is the remaining 20% that will be spent on the following April 1.