We have already looked at Genesis 14:20 and seen that a tithe is a one time gift of one tenth of all. The word is used 32 times in the KJV.The KJV translates Strong's H4643 in the following manner: tithe (27x), tenth part (2x), tenth (2x), tithing (1x).
Leviticus 27:30-32 King James Version (KJV)
30 And all the tithe of the land, whether of the seed of the land, or of the fruit of the tree, is the Lord's: it is holy unto the Lord.
31 And if a man will at all redeem ought of his tithes, he shall add thereto the fifth part thereof.
32 And concerning the tithe of the herd, or of the flock, even of whatsoever passeth under the rod, the tenth shall be holy unto the Lord.
The tithe of the land is a tenth of the annual increase. That is not the harvest. The farmer gets to deduct his seed or costs of production, as is stated in other verses.
Deuteronomy 14:22
Thou shalt truly tithe all the increase of thy seed, that the field bringeth forth year by year.
Some people sloppily speak of "tax" to support the church, but the bible uses that word only for money tributed to Egyptian or Roman government. Gifts to God or to Levites are never called a tax.
It is easy enough to look up the word "tithe" in any online bible. After you read 32 verses and whatever context catches your eye, you will know a few things. I mean things you didn't make up, like this "tax" baloney.
Oh, one more thing to remember: The name of the book, Leviticus, means "To The Levites". It does not apply to Christians. So don't "should" on yourself. The new testament says God loves a cheerful giver, so don't give until you can be cheerful about it.