Ala. Code § 40-18-5: Tax on Individuals.

The tax levied and imposed by Section 40-18-2 shall be computed as follows:

(1) For a single person, head of family, or married persons filing separate returns:

a. Two percent of taxable income not in excess of five hundred dollars ($500).

b. Four percent of taxable income in excess of five hundred dollars ($500) and not in excess of three thousand dollars ($3,000).

c. Five percent of taxable income in excess of three thousand dollars ($3,000).

(2) For married persons filing a joint return:

a. Two percent of taxable income not in excess of one thousand dollars ($1,000).

b. Four percent of taxable income in excess of one thousand dollars ($1,000) and not in excess of six thousand dollars ($6,000).

c. Five percent of taxable income in excess of six thousand dollars ($6,000).