Form 1040, Other Taxes section provides a total of the taxpayer's income tax plus the other taxes that may apply to the taxpayer. Adding the amounts on these lines together give the total tax. The total tax amount takes into account the tax on all income, adjustments to income, deductions, nonrefundable tax credits, and other taxes. The next step is entering tax payments and refundable credits. Then calculate the taxes owed, or the amount overpaid that would result in a refund.