How a Wisconsin paycheck works
Wisconsin's income tax has four rates, and its deduction works like Maine's rather than like most states': it is a fixed amount at low wages that slides down as earnings rise and vanishes entirely above a threshold. Wisconsin calls it a sliding scale standard deduction, and it is withdrawn quickly, so the effective rate climbs steeply across the lower and middle part of the salary range before settling.
Federal income tax withholding
Federal withholding annualises the wage, subtracts the standard deduction for the filing status on Form W-4 Step 1, applies the graduated schedule for that status, and deducts the dependent credit from Step 3. This page models a W-4 with Steps 2 and 4 blank: one job, no spouse income, no other income, no extra withholding.
Social Security and Medicare
Social Security takes a flat rate on wages up to an annual ceiling that moves each year. Medicare applies to every dollar, and above a fixed threshold the employer withholds the Additional Medicare tax on the excess.
The sliding scale deduction
Below a threshold the deduction is a flat amount. Above it, a fixed percentage of every extra dollar earned is taken off the deduction, until nothing is left. The withdrawal rate is steeper for married employees than for single ones, and both reach zero at a wage in the low seventies of thousands. Between the two thresholds each extra dollar is taxed twice over in effect, once directly and once by shrinking the deduction, which is why the marginal rate in that band is well above the schedule rate.
Exemptions claimed on the state certificate come off after the deduction and are worth a small fixed amount each; unlike the deduction they are not withdrawn as income rises. Wisconsin publishes only single and married columns, so head of household is withheld as single.
Local income tax
No Wisconsin municipality taxes wages. Milwaukee and Madison have identical payroll deductions.
What the employer pays on top
The employer matches Social Security and Medicare and pays federal unemployment tax at its net rate. Wisconsin unemployment insurance is an employer contribution at an experience-rated percentage on a state wage base. There is no employee-side state levy.
What this calculator assumes
The figure models a salaried employee paid evenly across the year with a standard Form W-4 and Form WT-4, and no pre-tax deductions. It leaves out:
- Pre-tax contributions such as a 401(k), health premiums, HSA or flexible spending accounts.
- Extra withholding requested on either certificate, and the W-4 Step 2 and Step 4 adjustments.
- Bonuses and other supplemental wages, which may be withheld differently.
- Employer-side Wisconsin unemployment insurance.
Withholding versus your final tax bill
Withholding is a prepayment. The federal and Wisconsin returns replace these assumptions with your real situation: itemised deductions, other income, and credits payroll knows nothing about, including Wisconsin's own school property tax and married couple credits. One job usually produces a refund; two jobs or a working spouse often produce a balance due.