Question Summary:
10% voluntary contribution in Islam?

Question Detail:

 I heard from my relative that like Sadaqah, Fitra and Zaka'at; there's one more head to spend that is to spend in Allah's name (around 10% of your income); though this is not obligatory. Please confirm.

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
There is no concept of 10% voluntary contribution in Islam.
 
And Allah Ta’āla Knows Best
Immad Bin Arshad
Student Darul Iftaa
California, USA
Checked and Approved by,
Mufti Ebrahim Desai.
www.daruliftaa.net