Tithing is a practice in the Catholic Church where each of the faithful is encouraged to give a portion of their income to benefit the Church and charitable organizations. Here's what scripture says about it: "On the first day of the week [Sunday] each of you should set aside whatever he can afford" (1 Corinthians 16:2).

Many Catholics donate 10% of their gross income, giving 5% to the Church and 5% to a favorite charity; however, tithing can be done in different ways. The Church wishes to emphasize that tithing is a gift and not an obligation. The Lord loves a cheerful giver!

Read more: https://www.catholic.com/qa/what-is-the-churchs-position-on-tithing