Even though he didn't pay income tax on it because it was under the Standard Deduction he does owe self employment tax on it to cover the Social Security and Medicare tax that wasn't taken out like on W2 wages. He pays both the employee and employer parts.
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% SE tax on 92.35% of your Net Profit (If it is 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 (FICA). So you get social security credit for it when you retire.
The SE tax is already included in your tax due or reduced your refund. It is on the 1040 Schedule 2 line 4 which goes to 1040 line 23. The SE tax is in addition to your regular income tax on the net profit.
You are paying 15.3% for…..
SS for employer 6.2%
SS for employee 6.2%
Medicare for employer 1.45%
Medicare for employee 1.45%
