(a) In general. (1) The time for payment of the estimated tax by individuals for calendar years shall be as follows:

(2) If, for example, due to the nature and amount of his gross income for 1955, the taxpayer is not required to file his declaration as of April 15, but is required to file the declaration on or before June 15, 1955, the case comes within the scope of subparagraph (1)(ii) of this paragraph and the estimated tax is payable in 3 equal installments, the 1st on the date of filing, the 2d on or before September 15, 1955, and the 3d installment on or before January 15, 1956.

(3) If a declaration is filed after the time prescribed in section 6073(a) (including any extension of time granted for filing the declaration), there shall be paid at such time all installments of the estimated tax which would have been payable on or before such date of filing if the declaration had been timely filed in accordance with the provisions of section 6073(a). The remaining installments shall be paid at the times and in the amounts in which they would have been payable if the declaration had been timely filed. Thus, for example, B, a single man who makes his return on the calendar year basis, was employed from the beginning of 1955 and for several years prior thereto at an annual salary of $6,000, thus meeting the requirements of section 6015(a). B filed his declaration for 1955 on September 16, 1955. In such case, B should have filed a declaration on or before April 15, 1955, and at the time of filing his declaration he was delinquent in the payment of three installments of his estimated tax for the taxable year 1955. Hence, upon his filing the declaration on September 16, 1955, three-fourths of the estimated tax shown thereon must be paid.

(4) In the case of a decedent, payments of estimated tax are not required subsequent to the date of death. See, however, paragraph (c) of § 1.6015(b)-1, relating to the making of an amended declaration by a surviving spouse if a joint declaration was made before the death of the decedent.

(5) The payment of any installment of the estimated tax shall be considered payment on account of the tax for such taxable year. Hence, upon the return for such taxable year, the aggregate amount of the payments of estimated tax should be entered as payments to be applied against the tax shown on such return.

(b) Farmers or fishermen. Special provisions are made with respect to the filing of the declaration and the payment of the tax by an individual whose estimated gross income from farming or, with respect to taxable years beginning after December 31, 1962, from fishing is at least two-thirds of his total gross income from all sources for the taxable year. As to what constitutes income from farming or fishing within the meaning of this paragraph, see paragraph (b) of § 1.6073-1. The declaration of such an individual may be filed on or before January 15 of the succeeding taxable year in lieu of the time prescribed for individuals generally. Where such an individual makes a declaration of estimated tax after September 15 of the taxable year, the estimated tax shall be paid in full at the time of the filing of the declaration.

(c) Amendment of declaration. If any amendment of a declaration is filed, the remaining installments, if any, shall be ratably increased or decreased, as the case may be, to reflect the increase or decrease in the estimated tax by reason of the amendment. If any amendment is made after September 15 of the taxable year, any increase in the estimated tax by reason thereof shall be paid at the time of making the amendment.

(d) Installments paid in advance. At the election of the taxpayer any installment of the estimated tax may be paid prior to the date prescribed for its payment.