As they say, everyone makes mistakes. In many situations, you can correct your error or just forget about it and move on. Making a mistake at work, however, can be more serious. It can have a dire effect on your employer. It may, for example, endanger a relationship with a client, cause a legal problem or put people's health or safety at risk. Repercussions will ultimately trickle down to you. Simply correcting your mistake and moving on may not be an option. When you make a mistake at work your career may depend on what you do next.
Admit Your Mistake: As soon as you discover that something went awry, immediately tell your boss. The only exception is, of course, if you make an insignificant error that will not affect anyone or if you can fix it before it does. Otherwise, don't try to hide your mistake. Doing that will make you look a lot worse if someone else discovers it and you could be accused of a coverup. Being upfront about it will demonstrate professionalism, a trait most employers greatly value.
Present Your Boss With a Plan to Correct the Error: There is one thing you should try to do before going to your boss—come up with a solution to rectify your mistake (along with a few alternatives for her to consider). If you can't come up with something quickly, go to your boss anyway, but reassure him that you are working on some solutions. Once you know what needs to happen, present your plan clearly. Tell your boss how long it will take to implement it and if there are any costs involved. Be ready to also present your alternative solutions just in case she shoots down the first one. Problem solving is an important soft skill.
Don't Blame Anyone Else: You may have collaborated with other employees on the project in question and, on some, level, each member of that team is responsible for its successes and failures. Ideally, everyone should approach your boss together to alert him to the mistake and take ownership of it. Unfortunately, that might not happen. There are going to be some people who say "not my fault." It won't help you to point fingers at others, even if they do share responsibility for the mistake. In the end, each person will be held accountable for his or her own actions.
Apologize But Don't Beat Yourself Up: There's a big difference between admitting your mistake and beating yourself up about it. Take responsibility but don't berate yourself for making it, especially in public. If you keep calling attention to your error, that is what will stick in people's minds. You want your boss to focus on your actions after you made the mistake, not on the fact that it happened in the first place.
If Possible, Correct the Mistake on Your Own Time: If you are exempt from earning overtime pay, get to work early, stay late and spend your lunch hour at your desk for as long as it takes to correct your mistake. This won't be possible if you are a non-exempt worker since your boss will have to pay you overtime—1 1/2 times your regular hourly wage—for each hour you work over 40 hours per week. You certainly don't want to stir up more trouble by causing him to violate that requirement.