Double time is a casual term that refers to the hours that someone works and be paid twice what he or she usually earned per hour.
Double time pay usually offered by employers to their employees when there is a shortage of workers.
This can often be due to public holidays, overtime, or working on off days.
It should be noted that while double time is essentially working for premium pay, premium pay is not necessarily double time as the wages might be less than the regular hourly rate.
Sudden unpredictable events are often the cause of ad-hoc double time requirements.
A customer service officer at a call center for example, might be doing shift work from Tuesdays to Saturdays. But because of a sudden spike in service calls, the management offers staff double time pay if they come back to work on their off-day on Sunday to attend to calls.
There is no standard to the circumstances where double time is required.
A company could very well choose to pay 50% more than regular pay rather than 100% more for calling people back to work.
Company policies might also require that staff would only be eligible for double time under certain circumstances.
For example, people who are on leave and choose to come back to work might not be eligible for premium pay rate. And only those who come back on off-days are eligible.
This is to prevent employees from gaming the system and max out their double time when there is no necessity for it.