There are mistakes and there are very serious mistakes. Some might be bad enough to give you the scare of your life and get you thinking about your current employment status. There is really no easy way to tell your boss that you have made a very big mistake, other than getting it over with as soon as possible. Your best bet for getting to keep your job would be to take a proactive stance. Look at the problem and try to offer solutions.
Admitting to a mistake may not necessarily be a career killer. It shows character and responsibility, if you do it gracefully. Too large a mistake and you might have to prepare yourself for a career ending move. But if you handle it right, this will prove that you are ready to take on calculated risks, and perhaps bigger responsibilities.
Timing is important. You’re an employee and you still hold a job. But if you risk losing it because of a big mistake, you need to find the best time to approach your boss. Being frank and willing to take blame for a mistake may be interpreted as a sign of strength in times of trial, so decide when and just get on with it. The sooner you tell your superiors, the better. This gives you time to redeem yourself, and it offers them time to make better-informed decisions.
Emphasize that it was an honest mistake. If it was, indeed, an honest mistake, being straightforward about it might be enough to save your job. To be sure, plan for the worst case scenario, and take responsibility. Finger pointing gives your boss the impression that you are blaming others for something that you have a direct hand in. We are humans, after all, and mistakes are part of the learning process.
Take the blame and the consequences of your actions. Skip the drama. If you approach the problem in a mature manner, this would help convince the boss you are not worth firing. Getting fired in today’s economic downturn is definitely not a good situation to find yourself in. People will make mistakes--plenty of them—and even your boss will, at one point, make mistakes. But taking responsibility and learning from past mistakes is part of professional growth.
Offer solutions. Give alternatives or work harder to make up for it and learn from your mistakes in life and the workplace. You could also provide solutions you have thought of so when asked what you are supposed to do about it, you’re ready.
Learn from past mistakes and charge these to experience. A new job after such a devastating blow to your career can be difficult, but not impossible. Should you end up getting fired and looking for work elsewhere, credit that particular big mistake to experience. If potential employers ask you about it, then be straightforward and honest, but focus on how you claimed responsibility and sought solutions.