Section 1.3-1 - Application of optional tax(a)General rules.(1) For taxable years ending before January 1, 1970, an individual whose adjusted gross income is less than $5,000 (or a husband and wife filing a joint return whose combined adjusted gross income is less than $5,000) may elect to pay the tax imposed by section 3 in place of the tax imposed by section 1 (a) or (b). For taxable years beginning after December 31, 1969 and before January 1, 1971 an individual whose adjusted gross income is less than $10,000 (or a husband and wife filing a joint return whose combined adjusted gross income is less than $10,000) may elect to pay the tax imposed by section 3 as amended by the Tax Reform Act of 1969 in place of the tax imposed by section 1 (a) or (b). For taxable years beginning after December 31, 1970 an individual whose adjusted gross income is less than $10,000 (or a husband and wife filing a joint return whose combined adjusted gross income is less than $10,000) may elect to pay the tax imposed by section 3 as amended in place of the tax imposed by section 1 as amended. See § 1.4-2 for the manner of making such election. A taxpayer may make such election regardless of the sources from which his income is derived and regardless of whether his income is computed by the cash method or the accrual method. See section 62 and the regulations thereunder for the determination of adjusted gross income. For the purpose of determining whether a taxpayer may elect to pay the tax under section 3, the amount of the adjusted gross income is controlling, without reference to the number of exemptions to which the taxpayer may be entitled. See section 4 and the regulations thereunder for additional rules applicable to section 3.(2) The following examples illustrate the rule that section 3 applies only if the adjusted gross income is less than $10,000 ($5,000 for taxable years ending before January 1, 1970). Example 1. A is employed at a salary of $9,200 for the calendar year 1970. In the course of such employment, he incurred travel expenses of $1,500 for which he was reimbursed during the year. Such items constitute his sole income for 1970. In such case the gross income is $10,700 but the amount of $1,500 is deducted from gross income in the determination of adjusted gross income and thus A's adjusted gross income for 1970 is $9,200. Hence, the adjusted gross income being less than $10,000, he may elect to pay his tax for 1970 under section 3. Similarly, in the case of an individual engaged in trade or business (excluding from the term "engaged in trade or business" the performance of personal services as an employee), there may be deducted from gross income in ascertaining adjusted gross income those expenses directly relating to the carrying on of such trade or business.Example 2. If B has, as his only income for 1970, a salary of $11,600 and his spouse has no gross income, then B's adjusted gross income is $11,600 (not $11,600 reduced by exemptions of $1,250) and he is not for such year, entitled to pay his tax under section 3. If, however, B has for 1970 a salary of $13,000 and incident to his employment he incurs expenses in the amount of $3,400 for travel, meals, and lodging while away from home, for which he is not reimbursed, the adjusted gross income is $13,000 minus $3,400 or $9,600. In such case his adjusted gross income being less than $10,000, B may elect to pay the tax under section 3. However, if B's wife has adjusted gross income of $400, the total adjusted gross income is $10,000. In such case, if B and his wife file a joint return, they may not elect to pay the optional tax since the combined adjusted gross income is not less than $10,000. B may nevertheless elect to pay the optional tax, but if he makes this election he must file a separate return and, since his wife has gross income, he may not claim an exemption for her in computing the optional tax.(b)Surviving spouse. The return of a surviving spouse is treated as a joint return for purposes of section 3. See section 2, and the regulations thereunder, with respect to the qualifications of a taxpayer as a surviving spouse. Accordingly, if the taxpayer qualifies as a surviving spouse and elects to pay the optional tax, he shall use the column in the tax table, appropriate to his number of exemptions, provided for cases in which a joint return is filed.(c)Use of tax table.(1) To determine the amount of the tax, the individual ascertains the amount of his adjusted gross income, refers to the appropriate table set forth in section 3 or the regulations thereunder, ascertains the income bracket into which such income falls, and, using the number of exemptions applicable to his case, finds the tax in the vertical column having at the top thereof a number corresponding to the number of exemptions to which the taxpayer is entitled.(2) Section 3(b) (relating to taxable years beginning after Dec. 31, 1964 and ending before Jan. 1, 1970) contains 5 tables for use in computing the tax. Table I is to be used by a single person who is not a head of household. Table II is to be used by a head of household. Table III is to be used by married persons filing joint returns and by a surviving spouse. Table IV is to be used by married persons filing separate returns using the 10 percent standard deduction. Table V is to be used by married persons filing separate returns using the minimum standard deduction. For an explanation of the standard deduction see section 141 and the regulations thereunder.(3) 30 tables are provided for use in computing the tax under the Tax Reform Act of 1969. Tables I through XV apply for taxable years beginning after December 31, 1969 and ending before January 1, 1971. Tables XVI through XXX apply for taxable years beginning after December 31, 1970. The standard deduction for Tables I through XV, applicable to taxable years beginning in 1970, is 10 percent. The standard deduction for Tables XVI through XXX, applicable to taxable years beginning in 1971, is 13 percent. For an explanation of the standard deduction and the low income allowance see section 141 as amended by the Tax Reform Act of 1969.(4) In the case of married persons filing separate returns who qualify to use the optional tax imposed by section 3, such persons shall use the tax imposed by the table for the applicable year in accordance with the rules prescribed by sections 4(c) and 141 and the regulations thereunder governing the use and application of the standard deduction and the low income allowance.(5) The tax shown in the tax tables set forth in section 3 or the regulations thereunder reflects full income splitting in the case of a joint return (including the return of a surviving spouse) and lesser income splitting in the case of a head of household. Therefore, it is possible for the tax shown in the tables relating to joint returns, or relating to a return of a head of a household, to be lower than that shown in the table for separate returns even though the amounts of adjusted gross income and the number of exemptions are the same.T.D. 7117, 36 FR 9420, May 25, 1971