What is military differential pay?

Some employers voluntarily agree to continue paying full wages to their employees who are called to active duty. This is commonly referred to as differential pay. Differential pay is any payment made by an employer to an individual for a period during which the individual is performing service in the uniformed services while on active duty for a period of more than 30 days and represents all or a portion of the wages the individual would have received from the employer if the individual were performing services for the employer.