As an employee, you likely receive wages, salaries or tips from your employer for your services. If so, you must include these amounts as part of your gross income when filing your taxes. Any withholdings are to be included in your income for the year they were withheld. Withholdings include Social Security, Medicare, and income tax.
Usually, contributions to a pension plan by your employer do not have to be included in your gross income, as well as certain withholdings compliant with salary reduction agreements between you and your employer. However, these amounts may still be subject to Social Security and Medicare taxes for the year they were withheld.
You will receive a W-2 from your employer that documents the total income you received as well as any withholding. This information will be required on your tax return, along with your spouse’s information, income and withholdings if you file jointly. You should attach a copy of all Form W-2s to your tax return, as per instructions. If you are self-employed, your income will be reported on a Form 1099-MISC, which you can use to file your return.
If you’ve already filed your tax return, and then receive an additional Form W-2, you will need to file an amended return using Form 1040X. You should receive all of your Form W-2s by January 31 in order to file your return before the deadline.