How an Indiana paycheck works
Indiana takes two bites at your wages, and both use the same arithmetic. The employer annualises your pay, subtracts a fixed amount for each exemption claimed on Form WH-4, and applies the flat state rate to what is left. Then it applies your county's rate to that same figure. Filing status never enters either calculation.
Every one of Indiana's ninety-two counties levies an income tax, so the county line is not an optional extra the way local tax is in most states. It is part of what everybody pays, and the rate varies enough between counties that it is worth knowing which one applies to you.
Federal income tax withholding
Federal withholding annualises the wage, subtracts the standard deduction that matches 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 left blank: one job, no spouse income, no other income, no extra withholding. Above the income limit for the status, the dependent credit tapers by a set amount for every thousand dollars of excess rather than disappearing at a cliff.
Social Security and Medicare
Social Security applies a flat rate to wages up to an annual ceiling that is re-indexed each year, so it stops partway through the year for a high earner. Medicare applies to every dollar, and above a fixed wage threshold the employer withholds the Additional Medicare tax on the excess, with no employer match and no regard for filing status.
Your county is decided on the first of January
The rule that surprises people is that county tax follows where you lived on 1 January, not where you live now. Move across a county line in March and your withholding does not change until the next January. If you live outside Indiana but work in an Indiana county, the county of your principal workplace supplies the rate instead.
The spread between counties is wide. The lowest rate is a small fraction of the highest, so two people on identical salaries in neighbouring counties can see a noticeably different county line. Some counties also carry rates with several decimal places, which is not a rounding artefact: the state publishes them that way.
Rates change. The department reissues its notice during the year and marks the counties that moved, so a payslip and this page can disagree if your county changed rate recently.
Form WH-4 and the exemptions
Form WH-4 has several exemption lines and they are worth different amounts. The personal exemptions on line 5 cover you, your spouse, and additional claims for being 65 or over or blind. The dependent exemptions on line 6 are worth more each than a personal one. There are two further lines this page does not model: a first-time additional dependent exemption and a larger exemption for an adopted child. If you claim either, your real withholding is lower than the figure here.
Whatever you claim comes off before both taxes, so an exemption saves you the state rate plus your county rate, not just the state rate. That makes exemptions worth appreciably more in a high-rate county.
Why filing status does not appear
Selecting married or head of household changes your federal withholding, and so changes the total, but it leaves both Indiana lines untouched. The state formula has no status term. A married couple adjusts Indiana withholding through the number of exemptions each of them claims on their own WH-4.
Short assignments in Indiana
An employer need not withhold Indiana state or county tax from an employee who is reasonably expected to work in the state for thirty days or fewer in the year, provided the right records or a signed affidavit exist. Cross that threshold and the tax for the earlier days becomes due as well. This page assumes a full year of Indiana work.
What the employer pays on top
The employer matches Social Security and Medicare and pays federal unemployment tax at its net rate. Indiana unemployment insurance is charged to the employer at a rate set from its own claims record on a state wage base, so it is left out. There is no employee-side state levy in Indiana: no disability insurance, no paid family leave premium.
What this calculator assumes
The figure models a salaried employee paid evenly across the year with a standard Form W-4 and Form WH-4, and no pre-tax deductions. It leaves out:
- Pre-tax contributions such as a 401(k), health premiums, HSA or flexible spending accounts, which reduce the wages subject to income tax and often to FICA.
- Extra withholding requested on the federal or state certificate, and the W-4 Step 2 and Step 4 adjustments.
- The first-time additional dependent and adopted child exemptions on Form WH-4.
- Bonuses and other supplemental wages, which may be withheld at a flat supplemental rate.
- Employer-side state unemployment insurance, which is priced per employer, and any federal unemployment credit reduction.
- Employees outside the normal Social Security system, such as some public-sector staff and certain visa holders.
Withholding versus your final tax bill
Withholding is a prepayment. The annual returns, federal and state, replace these standard assumptions with your real situation: itemised deductions, other income, and credits payroll knows nothing about. One job usually produces a refund; two jobs, a working spouse or investment income often produce a balance due.