Source:
Fatāwā Muḥammadiyyah, Vol. 1, Page 570
Question:
Teachers who tutor students often do not charge poor and needy children any tuition fees. At the end of the year, can such teachers deduct the value of these unpaid tuition fees from their Zakat payment — that is, consider it as part of their Zakat?
Answer:
Al-ḥamdu lillāh, waṣ-ṣalātu was-salāmu ʿalā Rasūlillāh, ammā baʿd!
This method of Zakat payment is not valid.
Therefore, such teachers should avoid deducting unpaid tuition fees from their Zakat.
Zakat must be actually paid and transferred to eligible recipients in a proper Shar‘i manner, not merely adjusted or symbolically offset.
هٰذَا مَا عِندِي وَاللّٰهُ أَعْلَمُ بِالصَّوَابِ
This is what I hold to be correct, and Allah knows best what is right.