Filing a Wisconsin tax return can seem daunting, especially if you are unfamiliar with state income taxes or the forms required. This guide is designed for Idaho, Missouri, and Iowa taxpayers who spent time in Wisconsin during 2015, along with small business owners, to simplify the process of completing a Wisconsin return. Whether you are preparing your first state return or filing on behalf of an S corporation, you will find clear, actionable steps to follow your federal income tax return and transition smoothly into Wisconsin’s requirements.

Accurate filing matters because errors can lead to delays in your refund, unexpected balances due, or even penalties and interest charged by the Wisconsin Department of Revenue. By understanding how Wisconsin forms integrate with your federal return and what documents you need to gather, you can minimize mistakes and ensure you claim credits like the homestead credit or tuition and fees subtraction. This approach helps you secure your fastest refund and avoid common pitfalls that cause processing delays.

All 2015 Wisconsin income tax returns were due on April 18, 2016. It is crucial to remember this date if you are filing an amended return, requesting an extension, or making estimated payments for subsequent tax years. In the following sections, you will find an overview of Wisconsin’s income tax structure for 2015, guidance on who must file, a rundown of key changes for that year, and detailed instructions for preparing, filing, and paying your Wisconsin return. By the end of this guide, you will be fully equipped to complete your Wisconsin state return confidently.

Overview of Wisconsin State Income Tax for 2015

Brief History and Structure of Wisconsin Income Tax

Wisconsin established its income tax in 1911 as one of the first states to tax personal earnings. Over the decades, the Wisconsin Department of Revenue refined the rate schedules and deduction rules to mirror federal income tax law changes while maintaining key state-specific provisions. By 2015, Wisconsin’s tax rates ranged from 4.0 percent to 7.65 percent, applied across graduated income brackets. The structure balanced revenue needs for state services—such as education and infrastructure—with taxpayer equity by allowing standard deductions and credits not found on federal returns.

How Wisconsin Forms Fit into the Federal Filing Process

Your federal adjusted gross income flows directly into Wisconsin Form 1 (line 1), where you apply state-specific additions and subtractions. Simple filers can use Form WI-Z or Form 1A, while nonresidents or part-year residents use Form 1NPR to allocate income correctly. This alignment cuts duplicate work and ensures you claim all Wisconsin credits and deductions.

Who Needs to File for 2015

Income Thresholds by Filing Status and Age

To determine whether you must file a Wisconsin return for 2015, compare your gross income against the thresholds based on filing status and age. These limits mirror federal filing status definitions while ensuring state taxes are paid only when income reaches levels that warrant a return.

  • Single under 65: You must file if your gross income was $10,950 or more in 2015. Filing ensures you report all taxable income and either pay any balance due to the Wisconsin Department of Revenue or claim a refund if you overpaid.

  • Single 65 or older: You must file if your gross income was $11,200 or more in 2015. This higher threshold accounts for the additional standard deduction for taxpayers sixty-five and older.

  • Married filing jointly, both spouses under 65: If your combined gross income was $19,860 or more in 2015, you must file. Filing jointly can simplify your Wisconsin return and lower your overall tax liability through shared deductions and credits.

  • Married filing jointly, one spouse 65 or older: If your combined gross income was $20,110 or more in 2015, you must file. This adjusted threshold recognizes the increased deduction available to the senior spouse.

  • Married filing jointly, both spouses 65 or older: If your combined gross income was $20,360 or more in 2015, you must file. The higher income threshold reflects the additional deduction for both spouses.

  • Married filing separately under 65: If your gross income was $9,470 or more in 2015, you must file. Filing separately can be beneficial in certain situations, but it may limit some credits on your Wisconsin return.

  • Married filing separately 65 or older: You must file if your gross income was $9,720 or more in 2015. The state standard deduction increases slightly for seniors, raising the filing threshold.

  • Head of household under 65: You must file if your gross income was $13,940 or more in 2015. This status typically applies to single parents or those supporting dependents, which offers a more favorable deduction.

  • Head of household 65 or older: You must file if your gross income was $14,190 or more in 2015. The higher filing threshold accounts for the age-based increase in the standard deduction.

Other Filing Triggers

Even if your income falls below the thresholds above, you may still need to file a Wisconsin return under certain circumstances. These additional triggers ensure you claim valuable credits and report withholdings or estimated payments correctly.

  • Wisconsin income tax withheld: If you had any Wisconsin state income tax withheld from your wages in 2015, you must file to claim a refund of those withholdings or apply them toward any tax due.

  • Estimated tax payments: If you made quarterly estimated payments using Form 1-ES or Corp-ES, you must file a return to reconcile those payments against your actual tax liability and avoid penalties.

  • Earned income, homestead, or veterans credits: If you qualify for credits such as the homestead credit, earned income credit, or veterans and surviving spouses property tax credit, you must file to claim these benefits on your Wisconsin return.

  • Nonresident or part-year residency: If you earned income in Wisconsin but did not live here for the whole year, you must file Form 1NPR to report Wisconsin-source income and ensure compliance with state tax rules.

By reviewing these filing requirements and triggers, you can determine whether you need to submit a 2015 Wisconsin return. In the next section, we’ll cover the key changes for the 2015 tax year that may affect your filing approach.

Key Changes for Tax Year 2015

Amended-Return Process (Form 1 + Schedule AR)

Starting in 2015, amended Wisconsin returns must use Form 1 with Schedule AR attached—Form 1X is no longer accepted. Check the “Amended Return” box and complete Schedule AR to explain any income, credit, or deduction changes, ensuring the Department processes your amendment without delays.

Standard Deduction Increase

For 2015, Wisconsin’s standard deduction amounts rose slightly for all filing statuses to reflect inflation. This larger deduction reduces taxable income more substantially for non-itemizers, often making the standard deduction the simpler, more beneficial choice.

Tuition/Fees Subtraction and College Savings Rollovers

The 2015 tuition and fees subtraction increased to $6,943 per student, lowering taxable income for qualified postsecondary expenses. Wisconsin now allows rollovers from other states’ 529 plans to qualify for this subtraction, encouraging education savings and providing direct state tax relief.

What Forms to Use

  • Form WI-Z: This form is designed for Wisconsin residents with simple tax situations who file a federal Form 1040EZ. It streamlines your filing by requiring only basic income and withholding information, making it faster and easier to complete your Wisconsin return.

  • Form 1A: Use this form if you have a slightly more complex situation, similar to federal Form 1040A, such as reporting certain tax credits or adjustments. It matters because it accommodates common credits like the homestead credit while still being more straightforward than the whole Form 1.

  • Form 1: This is Wisconsin residents' standard individual income tax return with complex tax scenarios, including multiple income sources or itemized deductions. It fits seamlessly into your federal filing process by beginning with your federal AGI and guiding you through Wisconsin-specific additions, subtractions, and credits.

  • Form 1NPR: Nonresidents and part-year residents use this form to allocate and report only the income earned in Wisconsin. This distinction ensures you pay state income tax solely on Wisconsin-source earnings and avoid overpaying on income taxed by other states.

  • Form 5S: S corporations report their income, gains, losses, deductions, and credits on this business return. The deadline is the 15th day of the third month after your tax year ends, and filing correctly is crucial to pass accurate income and credit information to shareholders via Schedule 5K-1.

Common Schedules and Attachments

  • Schedule WD: Use this schedule to report capital gains and losses, which adjust your Wisconsin taxable income if you sold investments during the year.

  • Schedule I: This schedule converts your federal AGI to Wisconsin AGI by listing additions and subtractions required under state law.

  • Schedule H or H-EZ: Attach this schedule to claim the homestead credit, providing relief on property taxes or rent for qualifying homeowners and renters.

  • Schedule PS: Use this new schedule to subtract private school tuition paid in 2015, reducing your state taxable income if you paid qualified expenses.

  • Schedule CS: Complete this schedule to claim the subtraction for contributions or rollovers into a Wisconsin college savings account.

  • Schedule FC or FC-A: Use these schedules to claim the farmland preservation credit if you owned or leased qualifying agricultural land.

  • Schedule OS: Attach this schedule to claim a credit for taxes paid to another state on income taxed by Wisconsin.

  • Schedule AR: This schedule must accompany any amended Form 1 to explain changes made when filing an amended return.

Step-by-Step Instructions to Complete Your Wisconsin Return

Step 1: Gather Your Documents

Collect all W-2 and 1099 forms, estimated payment records (Form 1-ES or Corp-ES vouchers), last year’s federal and Wisconsin returns, Social Security numbers, and any receipts for credits like tuition, homestead, or 529 rollovers, so you have every figure and supporting document ready before you start your Wisconsin return.

Step 2: Calculate Your Wisconsin AGI and Tax Liability

Transfer your federal AGI to line 1 of Form 1, add any Wisconsin-taxable income, subtract state-allowed deductions, then choose the larger of the standard deduction or itemized credits to arrive at taxable income; finally, apply credits and payments to determine whether you owe or will receive a refund.

Step 3: Complete and Review Your Return

Enter personal details and school district number, attach all required schedules (such as Schedule I, CS, PS, or business schedules), verify every calculation and Social Security number, and sign and date the form—unsigned returns will be returned and delay processing.

Step 4: File Your Return

You can e-file via Wisconsin’s official portal or compatible software for the fastest confirmation, or you can paper file using black ink and paper clips, mailing payment returns to PO Box 268, refund returns to PO Box 59, or homestead claims to PO Box 34 in Madison, WI.

Step 5: Make Payment or Set Up a Payment Plan

You can pay any balance through the no-fee TAP portal by credit card (with a 2.5 percent convenience fee), check, or money order made out to the Wisconsin Department of Revenue, or contact (608) 266-7879 to arrange an installment plan if you cannot pay in full.

Step 6: Track Your Refund or Balance Due

Use the “Where’s My Refund?” tool on revenue.wi.gov with your SSN and refund amount for the latest status, or call (608) 266-8100 (Madison) or 1-866-WIS-RFND; e-filed returns usually process in three weeks, while paper returns can take eight to twelve weeks.

How to File Your Return

Electronic Filing

E-filing your Wisconsin tax return through the Department of Revenue’s official portal or via third-party software such as TurboTax, H&R Block, or TaxAct ensures prompt confirmation that it has been received. Many tax preparers integrate state fees automatically when you file your federal return, and most e-filed Wisconsin returns are processed within three weeks, making e-filing the fastest way to get your refund.

Paper Filing

Complete Wisconsin Form 1 and any required schedules in black ink on the paper file, sign and date the return, and secure pages with paper clips. Mail payment returns to PO Box 268, Madison, WI 53790-0001, refund returns to PO Box 59, Madison, WI 53785-0001, and homestead credit claims to PO Box 34, Madison, WI 53786-0001. Using the correct address helps avoid delays and ensures your Wisconsin paper return reaches the proper department.

Extensions

Wisconsin honors federal extension requests, giving you 30 extra days beyond the April 18 filing deadline. If you miss the federal extension, you can still request a state-only extension of up to seven months. Remember that an extension to the filing does not extend the deadline to pay taxes owed—make an estimate and pay by April 18 to avoid 18% annual interest and late-payment penalties.

How to Make a Payment

Online via TAP

Use the Wisconsin Department of Revenue’s free TAP portal to pay your state tax liability electronically. Go to op.revenue.wi.gov/pay, select “Individual Income Tax,” and enter your Social Security number, tax year, and payment amount. Then provide your bank routing and account numbers to complete an electronic funds transfer with no convenience fees.

Credit Card Payment

Pay by MasterCard, Visa, Discover, or American Express through Official Payments Corporation at officialpayments.com or by calling 1-800-272-9829. Follow the prompts for Wisconsin state taxes, and note that a service convenience fee—about 2.5 percent of the payment (minimum $1)—will apply.

Check or Money Order

You can also pay by check or money order payable to “Wisconsin Department of Revenue.” On the memo line, write your Social Security number (or FEIN) and “2015 Tax Return” to ensure proper credit to your state account. Please paper-clip your payment to the front of your completed Form 1, and kindly avoid using staples.

If you owe a balance, mail your return and payment to:
Wisconsin Department of Revenue
PO Box 268,
Madison, WI 53790-0001

Payment-Plan Options

If you cannot pay your full state tax liability by April 18, 2016, you must file on time to avoid the failure-to-file penalty. You may pay as much as possible with your return and then request an installment agreement by calling the Wisconsin Department of Revenue at (608) 266-7879. Under a payment plan, you will make monthly payments until the remaining balance is paid in full. Interest at 18 percent per year will continue to accrue on the outstanding balance, but a structured payment plan can help you manage cash flow while remaining compliant with state tax requirements.

Estimated Tax Payments for 2016

Who Should Make Estimated Payments

You should make quarterly estimated payments if you expect to owe $500 or more on your 2016 Wisconsin income tax. This applies to self-employed individuals, small business owners, retirees with non-wage income, or anyone whose withholdings and credits won’t cover their liability, helping you avoid underpayment penalties.

Due Dates and Required Forms

Payments are due April 18, June 15, September 15, 2016, and January 17, 2017, using Form 1-ES for individuals or Corp-ES for corporations. To stay compliant and minimize interest charges, you can pay electronically via TAP or mail your voucher with a check or money order.

How to Track Your Refund or Balance Due

Monitoring the status of your Wisconsin refund or any balance due helps you stay informed and avoid unnecessary inquiries. The Department of Revenue offers multiple channels—online tools, phone lines, and mail options—to check where your return stands and when you can expect payment or notices.

Online Status Checks

You can use Wisconsin’s “Where’s My Refund?” feature at revenue.wi.gov to get real-time updates. You will need your Social Security number, the refund amount on your return, and your filing status. This tool provides the most up-to-date information on processing stages, any issues flagged, and the estimated deposit date for direct deposit refunds.

Phone and Mail Options

If you prefer to call or write, the department offers dedicated lines and an address for inquiries:

  • Madison Office: Call (608) 266-8100 for return status and payment questions.

  • Milwaukee Office: Dial (414) 227-4907 for regional assistance.

  • Toll-Free: Reach 1-866-WIS-RFND (1-866-947-7363) for automated or representative-assisted updates.

  • By Mail: Send a letter with your name, SSN, daytime phone, and details to Mail Stop 5-77, PO Box 8949, Madison, WI 53708-8949.

Typical Processing Times and Common Delays

  • E-filed Returns: Most refunds are issued within three weeks after acceptance.

  • Paper Returns: Allow eight to twelve weeks for processing, especially near the filing deadline.

  • High-Volume Periods: Returns filed close to April 18, 2016, may take longer due to increased workload.

  • Error or Review Flags: Missing signatures, math errors, or credit discrepancies (for homestead or tuition subtractions) can trigger manual review and extend processing times.

Refund Delivery Methods

  • Direct Deposit: The fastest, most secure option, credited directly to your bank account when you provide routing and account numbers.

  • Paper Check: Mailed to the address on your return; expect additional printing and postal delivery time.

Tracking your refund or balance due using these methods ensures you know exactly where your return stands and can

Individual Taxpayer Checklist

  • Completed and Signed Return: Ensure every page of Form 1 (or WI-Z/1A) is filled out correctly, all required signatures are present, and the date is included.

  • Attachments and Schedules: Verify you have attached all W-2s, 1099s, and Wisconsin schedules (I, H/H-EZ, WD, PS, CS, OS, AR) for credits and adjustments.

  • Math and Entry Review: Double-check all calculations, Social Security numbers, and filing status entries to avoid processing delays or notices.

  • Payment or Direct Deposit Information: If you owe tax, include payment or set up EFT via TAP; confirm your bank routing and account numbers if you expect a refund.

  • Copy for Records: Make and retain a complete copy of your federal and Wisconsin returns, including all attachments, for at least three years.

Small Business Owner Checklist

  • Business Schedules Attached: For sole proprietors, include Schedule C; for S corporations, attach Form 5S and Schedule 5K-1; for partnerships/LLCs, include Form 3 and 3K-1 schedules.

  • Estimated Payment Reconciliation: Confirm that any 2015 estimated payments you made on Form 1-ES or Corp-ES are applied on your return.

  • Credit and Deduction Documentation: Include supporting records for credits such as manufacturing/agriculture, research credits, and business-related subtractions.

  • Electronic Filing Requirements: Ensure corporate, partnership, and S-corp returns are filed electronically, or request a waiver if paper filing is necessary.

  • Future Planning: If you expect to owe more than $500 in 2016, set up quarterly estimated payments using Form 1-ES or Corp-ES to avoid underpayment penalties.

With this checklist completed, your 2015 Wisconsin tax filing is ready for submission. Ensure each item is addressed before mailing or e-filing to avoid delays, penalties, or missed credits.

Frequently Asked Questions

What if I missed the filing deadline for April 18, 2016?

If you missed the April 18, 2016, deadline, file immediately to limit penalties and interest. Wisconsin charges a failure-to-file penalty of five percent of unpaid tax per month (up to twenty-five percent) plus eighteen percent annual interest. Filing soon with the proper forms speeds up any refund and reduces additional charges from the Department of Revenue.

Can I use the IRS Direct File to submit my Wisconsin return?

IRS Direct File only applies to federal returns; you cannot file Wisconsin returns through it. Instead, file your state return via the Wisconsin e-file portal at revenue.wi.gov or through compatible software like TurboTax or TaxAct that supports federal and state filings. This ensures your Wisconsin data transfers correctly and simplifies the filing process.

How does the status of married filing separately affect my Wisconsin tax return?

Selecting married filing separately changes your Wisconsin standard deduction, income brackets, and credit eligibility. You will report only your income and withholding on Form 1, which can increase your tax compared to filing jointly. Compare Wisconsin deduction tables and credit thresholds before determining which status yields the lowest overall liability.

What deductions do Wisconsin taxpayers often overlook?

Wisconsin taxpayers often overlook subtractions and credits like the private school tuition deduction, homestead credit, college savings rollovers on Schedule CS, and credits for taxes paid to other states. Reviewing forms such as Schedule PS and OS helps identify these opportunities. Claiming all deductions and credits reduces your state tax liability and maximizes your refund.

How do I request an extension to file my Wisconsin return?

Wisconsin grants a 30-day extension beyond April 18 when you file a federal extension with IRS Form 4868. If you did not request a federal extension, you may apply for a state-only seven-month extension after April 18. Remember to pay any tax due by April 18 to avoid eighteen percent annual interest and late-payment penalties.

What if I need to amend my 2015 Wisconsin tax return?

To amend your 2015 Wisconsin return, file a new Form 1 and check the “Amended Return” box. Attach Schedule AR to explain changes and include any revised Schedules 5K-1 for S-corporation items. Submit within four years of the original due date to ensure smooth amendment processes. This ensures that the Department applies adjustments accurately.