Zakat On Service Sector
If you subtract expenses from your gross income then it becomes net income. Production zakat is due on gross income, not the net income. However, as Ghamidi sahab explained in the video shared above, if a certain expense is considered essential in that income (for example, salary of a person who actually performs the accounting tasks for a client) then it can be considered means of production and will be exempt from zakat. This is an ijtihadi matter so the actual application will have to be determined by you depending on your case. In my personal view, I would not deduct electricity charges, rent, etc. If your business requires financial investment as well as labor then your zakat would be calculated at 5% of gross, and if it requires only one and not the other then 10% of the gross.