Business Tithing - Tithing on the increase
The principle of tithing from a business is not dramatically different from tithing out of personal income. Actually, most of the Scriptures on giving in the Old Testament deal with business-generated income, since few people were actually employees in the sense they are today.
The vast majority of people in Old Testament times were employed in agriculture, as were most Americans prior to the 1930s. The precedent for tithing from a business is clear in God's Word.
Proverbs 3:9 says, "Honor the Lord from your wealth, and from the first of all your produce."
Notice that the reference here is to farming. However, figuring a business tithe is not necessarily as clear-cut as figuring the tithe on one's personal income. For example, you should tithe on the business' increase, which may not be the same as gross income.