Delaware Code Title 30. State Taxes § 1169. Declarations of estimated tax

(a) Every resident and nonresident individual or trust shall make a declaration of estimated tax for the taxable year in such form as the Director of Revenue may prescribe, if the estimated tax can reasonably be expected to exceed $800.  For the purposes of this section, the term “trust” shall mean any trust the fair market value of whose assets at the end of the tax year next preceding the tax year for which estimated taxes are otherwise required by this section equal or exceed $1,000,000.

(b) The term “estimated tax” means the amount which the individual or trust estimates to be the individual's or trust's income tax under this chapter for the taxable year, less the amount which the individual or trust estimates to be the sum of any credits allowable for tax withheld.

(c) If they are eligible to do so for federal tax purposes, spouses may make a joint declaration of estimated tax as if they were 1 taxpayer, in which case the liability with respect to the estimated tax shall be joint and several.  If a joint declaration is made but spouses determine their taxes under the chapter separately, the estimated tax for such year may be treated as the estimated tax of either spouse, or may be divided between them, as they may elect.

(d) An individual or trust may amend a declaration as prescribed by the State Tax Commissioner.