You fill out the 1040 form by calculating your adjusted gross income using the wages, tips, and other taxable income minus allowed deductions for your final amount, explains Turbo Tax. From there, deduct your standard or itemized deductions to result in your taxable income.
The IRS allows you to claim certain deductions and adjustments to determine your final adjusted gross income, including one-half of your self-employment tax payments, contributions to your individual retirement account, payments of student loan interest and health savings plan contributions, says Turbo Tax. From there, determine what amount is greater: the standard deduction or your itemized deductions to reduce your income. The final number is the amount of your income that is subject to taxes.
From there, determine how much tax you owe on your taxable income by referring to the tax tables that come with the 1040 form instructions. Compare your total tax withholding to your tax bill on the bottom of your form to determine if you have to pay tax or if you should expect a refund. You may also be able to reduce the amount of tax owed if you are eligible for certain tax credits, explains Turbo Tax.
Taxpayers who do not itemize deductions, do not have self-employment income, and fall below the income threshold can use the simpler Form 1040A. Taxpayers who meet those requirements and are also below age 65 and have no dependents may be able to use Form 1040EZ, which is the simplest version of this form.