Purity: Area of the Face Required to Be Washed in Wuḍūʾ

Practical Laws of Islam as per the teachings of Ayatullah Sistani

Ruling 236

The length of the face that must be washed is the area from the top of the forehead where the hair grows to the bottom of the chin; and the breadth of the face that must be washed is the area that is covered by the tip of the middle finger to the tip of the thumb. If even a small amount of this area is not washed, the wuḍūʾ is invalid; and if one is not certain of having washed this area completely, he must also wash a little extra around this area to be certain.

-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)