Delaware Code
Subchapter II. Resident Individuals
§ 1111. Credit for income tax paid to another state.

(a) Allowance of credit. — A resident individual shall be allowed a credit against the tax otherwise due under this chapter for the amount of any income tax imposed for the taxable year by another state of the United States, or the District of Columbia, on income derived from sources therein which is also subject to tax under this chapter.
(b) Limitation on credit. — The credit allowable under this section, with respect to the income tax imposed upon the taxpayer for the taxable year by each other taxing jurisdiction, shall not exceed the amount computed by multiplying the tax otherwise due under this chapter by a fraction, the numerator of which is the amount of the taxpayer's taxable income derived from sources in the other taxing jurisdiction (applying the rules of § 1122 of this title) and the denominator of which is the entire taxable income.