How to Calculate Tax Deductions for Wisconsin

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Calculating your Wisconsin tax deductions is not a complicated procedure. Under Wisconsin personal income tax law, taxpayers are eligible to claim both a standardized and itemized deduction on their state income tax return. The standardized deduction is available to all Wisconsin filers who meet the income filing requirements. The itemized deduction allows you to claim a credit for certain federal government deductions you can claim on schedule A of the federal income tax return.


  • Much like your federal tax return, you can incorporate a variety of deductions into your Wisconsin state income tax forms in order to ensure that you receive the largest tax refund possible.

Getting Started With Your Return

Calculate your Wisconsin income tax as required by law on Form 1, lines 1 through 13. Add your federal adjusted gross income to your state and municipal interest payments received plus any capital gains received. Then, subtract any state tax refunds you received from this total, as well as any United States government interest, unemployment compensation, or Social Security adjustment payments you received. The net total of this calculation can be found on line 14 of your Form 1 tax return. A copy of the Wisconsin Form 1 income tax return form can be obtained online at the Wisconsin Department of Revenue website.

Evaluating Your Deduction

Establish your standard deduction. For example, if you are single and earned between $14,960 and $101,460, your standard deduction would be $10,380 minus 12% of all additional income over $14,960. This information can be viewed on the income tax standard deductions table contained in the Wisconsin tax Form 1 instruction booklet, a copy of which may be viewed online at the Wisconsin Department of Revenue website.

Itemize your deductions on Schedule 1 of Wisconsin tax Form 1. This includes adding up all deductions you can claim from the federal government schedule A tax form, including medical and dental expenses, interest paid, gifts to charity, and casualty losses. The sum total of these deductions is your total itemized deduction amount.Subtract your standardized deduction from your total itemized deduction amount. For example, if you are a single filer and you earned $80,000 in 2017 and had $4,300 in total itemized deductions and $780 in standardized deductions, you would subtract $780 from $4,300 to arrive at $3,520.

Finalizing Your Calculations

Multiply the difference between your total itemized deductions and standardized deduction by 5 percent to calculate your Wisconsin itemized deduction credit. For instance, if the difference between your total itemized deductions and standardized deduction is $2,961, multiply this amount by 5 percent to arrive at your itemized deduction credit amount of $148.05.