Whether you have a legitimate excuse for running late to work or you just overslept, you can limit the damage by knowing how best to explain yourself. By being knowledgeable about your supervisor's policies and acting like a professional, you can call in late to work without earning the wrath of your boss.
Check Your Manual
Look at your employment manual, contract or employer guidelines to find out if there is a policy regarding how you to call in late to work. For example, the process might provide a number to call that will allow someone to notify your supervisor, or procedures regarding how much notice you should give. If you don't have a formal policy at your workplace, follow the protocol that your supervisors seem to approve of. For example, if they get agitated if other employees call in at the last minute, try to call as soon as you know you will be late.
Give an Excuse
When you have a valid excuse for being late, share it with your supervisor. If there was an accident on the freeway that has delayed your commute, call your supervisor immediately and let him know you'll be late, then ask if there are any pressing matters you should tackle first when you get to the office. If you were pulled over as you were rushing to work, show your boss the ticket. If you simply overslept, let your boss know you are running behind and will make up any missed time during lunch or after normal working hours.