Double-time pay is a compensation rate that is twice the normal wage rate. It is not required by federal law, but may be required for certain activities through a union contract or state law. For example, a union contract may stipulate that double-time pay is required for work during a major holiday, for an unusually onerous task, or for any overtime worked over a certain number of hours.
For example, the first 20 hours of overtime may be paid at 1.5x the normal pay rate, while all additional hours worked are at double-time. So, if an employee works a total of 65 hours in a week at a base rate of $20 per hour, the calculation of her pay is $20 per hour for the first 40 hours worked, then $30 per hour for the next 20 hours worked, and then $40 per hour for the final five hours worked, for a total pay amount of $1,600.