What is the airtime for a prepaid top-up? In this article Sim airtime is the total number of days you get each time credit is applied to your account. With every top up, your airtime resets to 120 days. You can dial *120# to check your airtime status. Related articles How can I check my balance? How to view your credit balance Prepaid Calling Rates How to request credit What is a prepaid call detail records request?