A tithe is 10 percent of an individual's gross income, and an offering is anything that is given above and beyond the tithe. While the tithe is a set percentage, no particular amount is expected for an offering.
The tithe is based on Old Testament verses that command individuals to give a tenth of their income to the church before any other bills are paid. Modern-day churches teach that the tithe should be taken from all sources of income, including investments and insurance checks. Churches also teach that tithing is an act of faith and a method of worship because it acknowledges that God is in control of the giver's life.