If you'd like some assistance in calculating proportional giving, here are two valuable tools. Either or both may be helpful in considering the financial commitment you believe is appropriate.
The first calculates percentages of your total income, making it easy to figure how much to contribute on a regular basis
The second makes it possible to determine what proportion/percentage of total income you are currently contributing through the church.

Question: "What does the Bible say about Christian tithing? Should a Christian tithe?"

Answer:  Many Christians struggle with the issue of tithing. In some churches giving is over-emphasized. At the same time, many Christians refuse to submit to the biblical exhortations about making offerings to the Lord. Tithing/giving is intended to be a joy and a blessing. Sadly, that is sometimes not the case in the church today.

Tithing is an Old Testament concept. The tithe was a requirement of the Law in which the Israelites were to give 10 percent of the crops they grew and the livestock they raised to the tabernacle/temple (Leviticus 27:30; Numbers 18:26; Deuteronomy 14:24; 2 Chronicles 31:5). In fact, the Old Testament Law required multiple tithes—one for the Levites, one for the use of the temple and the feasts, and one for the poor of the land—which would have pushed the total to around 23.3 percent. Some understand the Old Testament tithe as a method of taxation to provide for the needs of the priests and Levites in the sacrificial system.

The New Testament nowhere commands, or even recommends, that Christians submit to a legalistic tithe system. The New Testament nowhere designates a percentage of income a person should set aside, but only says gifts should be “in keeping with income” 1 Corinthians 16:2.

16:2  Upon the first day of the week let every one of you lay by him in store, as God hath prospered him, that there be no gatherings when I come.

Some in the Christian church have taken the 10 percent figure from the Old Testament tithe and applied it as a “recommended minimum” for Christians in their giving.

The New Testament talks about the importance and benefits of giving. We are to give as we are able. Sometimes that means giving more than 10 percent; sometimes that may mean giving less. It all depends on the ability of the Christian and the needs of the church. Every Christian should diligently pray and seek God’s wisdom in the matter of participating in tithing and/or how much to give James 1:5.

James 1:5  If any of you lack wisdom, let him ask of God, that giveth to all men liberally, and upbraideth not; and it shall be given him.

Above all, all tithes and offerings should be given with pure motives and an attitude of worship to God and service to the body of Christ. “Each man should give what he has decided in his heart to give, not reluctantly or under compulsion, for God loves a cheerful giver” (2 Corinthians 9:7).

Romans 1:20 For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:

An example of fine-tuning of the universe by GOD: If the mass and energy of the early universe were not evenly distributed to an incomprehensible precision of 1 part in 10^10^123, the universe would be hostile to life of any kind. This is an extraordinary figure. One could not possibly even write the number down in full, in our ordinary denary (power of ten) notation: it would be one followed by ten to the power of 123 successive zeros!

(That is a million billion billion billion billion billion billion billion billion billion billion billion billion billion zeros.)