Schedule SE calculates the tax due on your self-employment earnings. Generally speaking, you must pay self-employment tax if you earned $400 or more in self-employment income.
Schedule SE provides information to the Social Security Administration which uses it to calculate your benefits under the social security program. You should note that self-employment tax applies to you regardless of age, even if you are already old enough to collect social security and Medicare benefits.
Part I of Schedule SE is divided into two sections: Short Schedule SE and Long Schedule SE. Use the flowchart at the top of the form to determine which section you should complete.
There are multiple exceptions that you need to be aware of, but in general those who received wages and tips over the course of the tax year must complete Long Schedule SE; those who did not receive wages or tips can use Short Schedule SE.
You should note that the maximum amount of self-employment income subject to social security tax is set at $106,800.