How to Prepare Your State Tax Return

State Income Tax form and a pencil
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It’s that time of year again. Not only do you have to worry about your federal tax return, but there’s also that pesky state income tax return - unless you live or work in one of the few states that do not have an income tax.

Where to Start

The starting point for just about every state income tax return is your federal return. You’ll want to be sure that your federal return is accurate and complete before you even think about preparing your state return.

Adjusting Your Federal to State Income

Once you have entered the information from your federal return on your state income tax return, you’ll begin making adjustments to it to reconcile the differences between your federal taxable income and your state taxable income. 

Some of these adjustments will be additions. Such additions are usually add-backs of any federal deductions you may have taken that are not allowed on your state return. They may also be income items that are tax-exempt for federal purposes but are taxed at the state level. 

Other adjustments will be subtractions. These are usually for income items that are taxable under federal tax law but are tax-exempt under state tax law. Some of these subtractions may also be state-specific deductions. The amount of adjustments your tax return will require depends on what extent your state conforms to the federal tax code.

Additions to State Taxes

Common state additions to federal taxable income include:

Subtractions From State Taxes

Common state subtractions to federal taxable income include:

  • Deduction for federal income taxes, if your state offers this deduction 
  • Contributions to your state’s 529 college savings plan
  • Social Security and other retirement benefits that are taxed federally
  • State income tax refunds
  • State lottery winnings

Figuring Your Tax Liability

Once you have calculated your taxable income for state income tax purposes, you will find your gross state tax liability. Some states have one flat tax rate that all taxpayers pay regardless of income. However, most states have tax brackets with tax rates that increase as income increases. In these states, you’ll have to use a table to calculate your tax.  

Calculating Your Amount Due

Once you have your tax liability, you will reduce that by any state tax credits you qualify for. State tax credits vary widely among states, but many states have their versions of child tax credits and earned income credits. Most tax credits can only reduce your tax liability to zero, but there are some refundable tax credits, meaning that they are treated as a payment of tax with any leftover credit being refunded to you.

Filing Your Return

Preparing and filing your return electronically is the preferred method for tax compliance. You will have a more accurate return if you use a software program and you will get your refund faster if you e-file and choose direct deposit. Many states have lists of free software programs you can use on their websites. 

Purchased tax software programs—like Turbo Tax—usually include state tax return preparation for most, but usually not all, states. Check the list of states available with the product before you purchase the software.