You must file Schedule SE (self-employment income) if:
Your net earnings from self-employment from other than church employee income were $400 or more, or
You had church employee income of $108.28 or more.
You must pay SE tax if you had net earnings of $400 or more as a self-employed person. If you are in business (farm or non-farm) for yourself, you are self-employed. You must also pay SE tax on your share of certain partnership income and your guaranteed payments.
If you had church employee income of $108.28 or more, you must pay SE tax. Church employee income is wages you received as an employee (other than as a minister or member of a religious order) of a church or qualified church-controlled organization that has a certificate in effect electing an exemption from employer Social Security and Medicare taxes.
For more information, see Instructions for Schedule SE (Form 1040) on the IRS web site.