In most cases, you are not permitted to deduct from the salary of an exempt employee for a partial day of absence. Exempt employees generally must be paid their full salary for any day in which they perform any work. An exception does exist for partial day absences taken as intermittent leave under family and medical leave laws.
Employers may deduct from an employee's salary for absences in increments of full working days in certain circumstances.
Keep in mind that these rules do not apply to nonexempt employees. Nonexempt employees need only be paid for the actual time they work.
Read more Deductions from an Exempt Employee's Salary in the HR Library.