Wisconsin payroll taxes come down to three obligations for most employers: withholding state income tax from each paycheck, paying state unemployment insurance tax on the first $14,000 of each worker’s wages per year, and carrying workers’ compensation insurance once your workforce or payroll crosses a low threshold. There are no city or county payroll taxes anywhere in the state. Two agencies run the system: the Department of Revenue handles income tax withholding, and the Department of Workforce Development handles unemployment insurance and workers’ comp.
State Income Tax Withholding
Every employer paying wages for work performed in Wisconsin must withhold state income tax from each paycheck. The amount depends on the employee’s filing status, the number of withholding exemptions they claim, and where their pay falls across Wisconsin’s four tax brackets, which run from 3.50 percent at the bottom to 7.65 percent at the top.1Department Of Revenue. Tax Rates
Have each employee complete Form WT-4, the Employee’s Wisconsin Withholding Exemption Certificate. It’s separate from the federal W-4, and if an employee never turns one in, you must withhold at the highest default rate as though they are single with zero exemptions.2Wisconsin Department of Revenue. Employee’s Wisconsin Withholding Exemption Certificate WT-4 The Department of Revenue’s Publication W-166 contains withholding tables that convert exemptions and pay periods into exact dollar amounts, so you don’t need to calculate bracket math yourself.3Wisconsin Department of Revenue. Withholding Tax
Bonuses, Commissions, and Overtime
Supplemental pay issued alongside a regular paycheck is combined with the regular wages and run through the standard tables. When you issue supplemental pay separately between regular payroll periods, you can instead use a flat percentage tied to the employee’s estimated annual gross salary: 3.54 percent for earnings under $12,760, stepping up through 4.65 percent and 5.30 percent, and reaching 7.65 percent at $280,950 and above.4Wisconsin Department of Revenue. Withholding Tax Guide The flat rates apply only to supplemental payments; regular wages always go through the tables.
State Unemployment Insurance Tax
Wisconsin’s unemployment insurance tax funds benefits for workers who lose jobs through no fault of their own. Employers pay the full cost. It cannot be deducted from employee wages.
For 2026, the taxable wage base is $14,000 per employee. Once a worker’s year-to-date wages pass that threshold, additional wages must still be reported but are not taxed.5Department of Workforce Development. Unemployment Insurance 2026 Tax Rates
New Employer and Experience Rates
New employers start at a standard rate set by payroll size: 3.05 percent for businesses with payroll under $500,000 and 3.25 percent for those at or above $500,000.5Department of Workforce Development. Unemployment Insurance 2026 Tax Rates After a few years, the state assigns an experience rating based on how many unemployment claims former employees have filed against your account. Stable employers with strong reserve balances can drop to 0.00 percent (smaller payrolls) or 0.05 percent (payroll of $500,000 or more). Employers with heavy turnover and deeply negative reserves can reach the maximum 12.00 percent. Schedule D is the rate schedule in effect for 2026.
Quarterly Deadlines
UI reports and payments are due every quarter:
- First quarter (January–March): due April 30
- Second quarter (April–June): due July 31
- Third quarter (July–September): due October 31
- Fourth quarter (October–December): due January 31
If a due date lands on a weekend or legal holiday, the deadline moves to the next business day.6Department of Workforce Development. Part 4 – Account Reporting, Section 2 – Tax Employers at a zero rate still have to file the quarterly reports.
Workers’ Compensation Insurance
Wisconsin requires most employers to carry workers’ compensation insurance, and the threshold is low. The requirement applies when any of these are true:
- You employ three or more workers, full-time or part-time. Coverage is required the day the third worker is hired.
- You pay $500 or more in gross wages in any quarter, even with a single employee. Coverage is required on the tenth day of the first month of the following quarter.
- You are a farmer employing six or more workers on the same day for at least 20 days during the calendar year.
Once required, coverage must stay in place as long as you have at least one employee.7Department of Workforce Development. Worker’s Compensation Insurance Requirements in Wisconsin
Operating uninsured is expensive. The Department of Workforce Development can assess double the premiums you should have been paying during the uninsured period, or $750, whichever is greater, plus up to $100 per day for up to seven days. The department can also order the business shut down, and if a worker is injured during the uninsured period, you can be held personally liable for their claim benefits.7Department of Workforce Development. Worker’s Compensation Insurance Requirements in Wisconsin
Workers Who Cross State Lines
Wisconsin has income tax reciprocity agreements with Illinois, Indiana, Kentucky, and Michigan. When an employee lives in one of those four states but works in Wisconsin, don’t withhold Wisconsin income tax. The employee pays income tax to their home state instead. The reverse is also true: a Wisconsin resident working in one of those four states owes tax only to Wisconsin.8Wisconsin Department of Revenue. Individual Income Tax Working in Another State
Reciprocity covers wages, salaries, commissions, and similar employee compensation only. It does not reach rental income, investment gains, or lottery winnings. Confirm each cross-border employee’s state of residence and apply the correct withholding; mistakes near the Illinois or Michigan borders are common and create problems at tax time for both sides.
Setting Up Payroll Tax Accounts
Before you run your first payroll, you need accounts with the IRS and with the state. Start with a Federal Employer Identification Number if you don’t already have one; the IRS issues EINs to any business that has employees or pays employment taxes.9Internal Revenue Service. Employer Identification Number
Register for a Wisconsin withholding tax account through the Department of Revenue’s online Business Tax Registration system. You’ll need your FEIN, the legal name and physical address of the business, and identifying information for the owners or officers.10Wisconsin Department of Revenue. Business Tax Online Registration A separate registration with the Department of Workforce Development opens your unemployment insurance account.
For each employee, collect the full name, address, and Social Security number, and have them complete both the federal W-4 and the Wisconsin WT-4. Report every new hire to the Wisconsin New Hire Reporting Center within 20 days of their start date. Rehired workers returning after a gap of more than 60 days must also be reported.11Department of Workforce Development. Wisconsin New Hire Reporting
How Often to Deposit and File
Withholding Deposits
All withholding deposits are filed electronically through the Department of Revenue’s My Tax Account portal using Form WT-6. Your deposit frequency depends on how much you withhold in a calendar year:
- Quarterly: total annual withholding of $300 or less
- Monthly: more than $300 but not more than $2,500
- Semi-monthly: more than $2,500 but not more than $40,000
- Eighth-monthly: more than $40,000
Missing a deposit deadline triggers escalating penalties, so the threshold you fall into matters.4Wisconsin Department of Revenue. Withholding Tax Guide After the calendar year ends, every employer files Form WT-7 by January 31 to reconcile deposits against the amounts reported on W-2 forms. The system rejects the reconciliation if the numbers don’t line up, so catch any discrepancies before you submit.12Wisconsin Department of Revenue. Instructions for Preparing the Employer’s Annual Reconciliation of Wisconsin Income Tax Withheld WT-7
Unemployment Insurance Filings
UI reports and payments go through the Department of Workforce Development’s UI Employer Portal at unemployment.wisconsin.gov. Quarterly wage reports and tax payments are submitted there, and payments can be made via electronic funds transfer.13Department of Workforce Development. Welcome to UI Employer Portal Save the confirmation numbers; they are your proof of filing if the account is ever audited.
Penalties for Late or Incorrect Filings
Wisconsin’s withholding tax penalties under Section 71.83 stack, which is what makes a small mistake expensive:
- Incomplete or incorrect reports: a 25 percent penalty on the amount not properly reported, withheld, or deposited. Applies to both WT-6 deposits and the WT-7 annual reconciliation.
- Late filing: 5 percent of the tax due per month, up to a 25 percent cap.
- Late filing fee: $50 for most employers, $150 for corporations and insurance companies.
- Delinquent interest: 1.5 percent per month, or 18 percent annually, on unpaid amounts.
- Intentional failure to withhold: a penalty equal to the entire amount that should have been withheld, plus interest and additional penalties. Officers and other responsible persons can be held personally liable.
- Criminal penalties: willfully failing to deposit or pay withheld taxes, or filing a fraudulent report, is a misdemeanor punishable by a fine of up to $10,000, imprisonment of up to nine months, or both.
An employer who files an incorrect WT-6 two months late could face the 25 percent accuracy penalty, the 10 percent late-filing surcharge, the $50 late fee, and 1.5 percent monthly interest, all on the same underpayment.14Wisconsin Department of Revenue. DOR General Withholding Tax Questions
Payroll Records You Have to Keep
Wisconsin requires employers to keep payroll records for at least three years. The records must be stored at the place of employment or at a central recordkeeping office in the state, and they must include each employee’s name and address, dates of employment, daily and weekly hours worked, pay rate, wages paid each period, and every deduction with the reason for it.15Wisconsin Department of Workforce Development. Permanent Records
For withholding tax purposes, the Department of Revenue generally expects records to be available for four years from the later of the return’s due date or the date it was filed. Keeping WT-4 forms, copies of W-2s, and deposit confirmations for four years covers both the labor and tax requirements with margin to spare.