Many people are terrified when doing their taxes, thinking that one small mistake is going to trigger an audit and leave them facing fines, fees and even jail time. They think of the IRS as this aggressive organization that is carefully watching their every move, ready to pounce just because of a simple mathematical error on a form they were never really taught how to fill out in the first place.
Mistakes on your taxes can trigger audits. You may have to pay fines or fees if you make errors, especially if you were clearly careless.
That being said, the IRS isn't as aggressive about this as most people assume. In many cases, they'll just adjust small errors on their end. You may get a notification in the mail telling you it's been done. Yes, you may have to pay more if you really owed more than you thought, or your return may shrink, but this isn't a huge issue. The IRS is just fixing the documents so you pay the proper amount.
The only time you're really in trouble is when you make huge mistakes -- not paying $5,000 or more -- or when you clearly try to intentionally defraud the government. For example, purposely trying to hide some of your income or intentionally refusing to report it could bring about fraud charges. If you just accidentally left something out or made a small mistake, though, things aren't nearly this dire. Tax fraud is intentional.
If you are facing tax issues stemming from these types of errors, make sure you know exactly what the IRS is likely to do and the legal options that you have. You should try to do your taxes correctly, but most errors can be easily fixed with the proper steps.
Source: The Nest, "Does the IRS Forgive Honest Mistakes?," John Csiszar, accessed Dec. 02, 2016