In Islamic zakat terminology, one complete lunar year of wealth ownership is called hawl.
For many forms of zakatable wealth, a hawl is one condition associated with liability: the wealth must remain at or above the relevant threshold for a lunar year. The commonly cited rate for qualifying monetary wealth is 2.5 percent, although detailed rules differ among legal traditions and asset types.
Hawl should not be confused with nisab. Nisab is the minimum threshold of wealth, while hawl refers to the passage of a lunar year. Some categories, including agricultural produce and certain newly acquired wealth, have different rules concerning when zakat becomes due.
Because the Islamic calendar is lunar, a hawl is approximately 354 days rather than a solar year of about 365 days.