You usually must pay self–employment tax if you had net earnings from self–employment of $400 or more. Generally, net earnings from self–employment represent 92.35% of your net profit. Net profit is calculated by subtracting ordinary and necessary trade or business expenses from your total self–employment income. You are self–employed for this purpose if you are a sole proprietor, an independent contractor, a member of a partnership, or are otherwise in business for yourself. You can be liable for paying self–employment tax, even if you are currently receiving social security benefits.

If you had a small profit or net loss from your business but want to pay into the social security system, you may be eligible to file Schedule SE and use one of the two optional methods to compute your net earnings from self–employment. Refer to Publication 533, Self–Employment Tax, to see if you qualify to use an optional method. An optional method may increase your earned income credit or the child and dependent care credit.

The total tax rate for 2003 is 15.3% of your net earnings from self–employment. This rate is the total of 12.4% for Social Security and 2.9% for Medicare. The maximum amount of net earnings subject to the social security part is $87,000 in 2003. All of your net earnings are subject to the Medicare part. Self–employment tax is computed on Form 1040, Schedule SE (PDF), and reported on line 55 Form 1040 (PDF) for 2003. When figuring your adjusted gross income on Form 1040, you can deduct one–half of your self–employment tax on line 28, Form 1040. The Social Security Administration uses the information from Schedule SE to figure your benefits under the social security program.

If you are an employee of a church or qualified church–controlled organization that elected exemption from social security and Medicare taxes, you must pay self–employment tax if you are paid $108.28 or more in a year. If you are required to pay self–employment tax, you must file Form 1040 and attach Schedule SE. For more information on church related income and self–employment taxes refer to Publication 517, Social Security and Other Information for Members of the Clergy and Religious Workers.

More information on self–employment tax can be found in Publication 533.