Hopefully your income shows up on the 1040 line 12 and not line 21 for other income. You should have a schedule C for self employment income. If you have a net profit of $400 or more you will pay 15.35% SE tax.
Self Employment tax (Scheduled SE) is automatically generated if a person has $400 or more of net profit from self-employment. You pay 15.3% for 2013 SE tax on 92.35% of your Net Profit greater than $400. The 15.3% self employed SE Tax is to pay both the employer part and employee part of Social Security and Medicare. So you get social security credit for it when you retire. You do get to take off the 50% ER portion of the SE tax as an adjustment on line 27 of the 1040. The SE tax is already included in your tax due or reduced your refund. It is on the 1040 line 56. The SE tax is in addition to your regular income tax on the net profit.
