Not quite. The tithe, as prescribed in the Torah, is 10% of the increase, and only on agricultural income (which is why Jesus talked about the Pharisees’ scrupulosity in tithing mint and cumin). The “increase” is whatever you have this year is more than what you had last year. So if I sowed a bushel of wheat and reaped 10 bushels, the increase is 9 bushels, and the tithe is 0.9 bushels. If the ewes in my flock had 10 lambs, that’s the increase, and the tithe is one lamb. There is nothing-zero-zip-nada in the Old or New Testaments about tithing any other income, except for saying that Abraham gave a “tithe” of the spoils of his war with the five kings to Melchizedek.
Anything that has been added to the law of the tithe, as it is stated in the Torah, is human tradition and can be followed or abandoned, however one pleases. That said, giving 10% of one’s income is a good place to start. 10% of the “increase,” as the Torah taught, would be 10% of whatever lands in your bank account; the “increase” is what you actually get. If you are moved to give 10% of your gross income, go right ahead. But the Biblical tithe is 10% of the increase of the agricultural harvest, period.