First the basics. Christians are not required to tithe. We are exhorted to give money to support those who run the church (1 Timothy 5:17-18) (which would include ministry/office space such as a church building), support those who reach others with the gospel (1 Corinthians 9:14) (AKA: parachurch ministries and missionaries), and provide for the needy (1 John 3:17-18). Nowhere does the New Testament tell believers they must give ten percent of their income to the church.
When tithing a percentage of my income, should it all go to my home church or can I give some to a Christian ministry?
The two standards for giving are merely that it be done cheerfully (2 Corinthians 9:7) and "in keeping with income" (1 Corinthians 16:2 NIV). The "tithe" or ten percent is now a cultural custom, not a biblical mandate. It is a handy guideline. God will ask believers to give more or less depending on the circumstances, but it's a fair place to start the discussion.
So if we're not required to give a set amount, and if the New Testament tells us to provide for three categories of people, how do we decide how much to give to whom? The Bible doesn't say. There is no hard and fast rule. In general, many preachers say to give ten percent to the church as a tithe and give other donations to parachurch ministries and the needy, but, again, that's a cultural guideline. As a member of a local body of believers, it's every church-goer's responsibility to make sure the needs of the church are met as the church practices good stewardship. In addition, the Bible says to support those outside the local church and give to the needy. But the Bible doesn't say how much or in what portion.
Part of developing spiritual maturity is learning to hear God's personal will. Every believer should pray and ask God how they are supposed to give. As long as we understand that everything we have is a gift from God and He wishes us to use it to support the church, ministries, and the needy, we don't need rules to dictate the specifics. If God brings a need to your attention, do what you can to fill it.
Christian tithing - What does the Bible say?
What was God's purpose in establishing the church?
Christian ministry - What is it?
How can I seek first the kingdom of God?
What does it mean to be a cheerful giver?
Truth about the Christian Life