If you have multiple unrelated businesses organized as sole proprietorships/single member LLCs, you generally should prepare separate Schedule C forms for each to report your business income or losses. Separate Schedule C forms are typically filed for each spouse that has their own business as well.
The results of the various businesses are combined on your Form 1040 and added to your other income in determining your taxable income. In addition to paying income tax on your business, you will also need to pay self-employment taxes including Social Security and Medicare taxes. These taxes are calculated using Schedule SE with your Form 1040 tax return. If you have multiple sole proprietorship businesses, you combine the results of these into a single amount that you then use with your Schedule SE and flow through to your Form 1040. As with the Schedule C, if spouses have separate businesses, each spouse will prepare their own Schedule SE since self-employment taxes are calculated separately for each worker.
Ruth C-L, CPA, Atty.
