You "really" need to provide more details. Why would someone have two SCH C's for two "similar" businesses? There are valid reasons. But still, incorrect assumptions are easy to make with the little amount of information you've provided. My initial impression is that you have one business that, when started was owned by you and your spouse. You live in one of the community property states that allows a married couple with a joint business to split the income/expenses between the two of you by filing a SCH C for each of you on your joint return, with all income/expenses divided equally between the two SCH C's. Those states are Louisiana, Arizona, California, Texas, Washington, Idaho, Nevada, New Mexico, and Wisconsin.
Now, something has happened such as separation, divorce, or one of you no longer wants the business, or the two of you are filing Married Filing Separate, and the other one person (you) now owns and reports all business income/expenses on a single SCH C.
So you "really" need to provide more details to paint a clearer picture of what's going on here. Otherwise, you risk those responding to you making incorrect assumptions resulting in information that causes you to do something that begs for an audit. Otherwise, this is one of those situations where the accuracy of the answer is directly proportional to the clarity of the question.
Why do you now need to combine two SCH C's into one?
Are there depreciable assets involved on both SCH C's?
