Estimated Tax Simplification Act of 1983

Estimated Tax Simplification Act of 1983 - Amends the Internal Revenue Code to revise provisions dealing with the quarterly payment of estimated tax by individuals. Establishes the amount of the penalty for underpayment of estimated tax at the amount of the underpayment for the period of underpayment, plus interest on such amount. Revises the schedule for the payment of estimated tax installments. Specifies that the amount of the required annual estimated tax payment shall be the lesser of 80 percent of the current tax shown on the taxpayer's return or 100 percent of the preceding year's tax liability. Permits lower estimated tax payments if the taxpayer can show that the installment payments made over the year were adequate for each quarter based on an annualized income concept.

Exempts a taxpayer from an estimated tax penalty: (1) where the tax liability is less than $500; (2) where there is no tax liability for the preceding taxable year; or (3) where there is reasonable cause for the underpayment. Exempts a taxpayer from a penalty for underpayment of estimated tax for the fourth quarter if such taxpayer files on or before January 31 of the following taxable year a return and pays any tax liability in full (March 1 for farmers and fishermen).

Permits farmers and fishermen to make only one annual estimated tax payment on January 15 of each year. Lowers the percentage of the required estimated tax payment for such farmers and fishermen to 66-2/3 percent of the tax shown on their returns.

Requires the Secretary of the Treasury to prescribe regulations to carry out the provisions of this title.

Repeals provisions of the Internal Revenue Code dealing with the declaration of estimated tax by individuals, the time for filing declarations of estimated tax, and installment payments of estimated income tax by individuals.

Allows an income tax deduction for the amount of the penalty paid for the underpayment of estimated tax.