To fill out the Ohio IT 4, give your employer your name, Social Security number, and address at the top, then work through Section II to add up your exemptions: one for yourself, one for a spouse if you’re filing jointly, and one for each dependent you’ll claim on your Ohio return. Add an optional dollar amount on Line 5 if you want extra tax withheld. If you live in one of Ohio’s taxing school districts, enter the district’s name and its four-digit number. Sign it and hand it to payroll. The form stays with your employer and is never sent to the state.1Ohio Department of Taxation. Employee’s Withholding Exemption Certificate IT 4 Instructions
If you never turn one in, your employer must withhold as though you claimed zero exemptions, which means more tax comes out of every paycheck than you probably owe.2Ohio Department of Taxation. Employer Withholding Reciprocity
Get These Ready Before You Start
The form is short, but a couple of details slow people down. Have your full legal name, Social Security number, and current home address in front of you. Decide how you’ll file your Ohio return: single, married filing jointly, or married filing separately. That answer sets how many exemptions you can legitimately claim.
If your home address falls inside one of Ohio’s 214 taxing school districts, you also need the district’s name and its four-digit number. The Ohio Department of Taxation’s free lookup tool, The Finder, returns both when you type in your address.3Ohio Department of Taxation. The Finder – School District Income Tax Lookup By Address The form is available from your employer’s payroll or HR office, or you can download it from the Department of Taxation website.
Section I: Your Personal Information
The top block asks for name, Social Security number, and address. These need to match what the IRS has on file, because Ohio piggybacks on the federal dependent rules.1Ohio Department of Taxation. Employee’s Withholding Exemption Certificate IT 4 Instructions Check your Social Security number twice. A single wrong digit can send your withholding to the wrong account and turn tax season into a paperwork chase.
Section II: Working Through Your Exemptions
Section II is where the arithmetic happens. There are five lines and each one feeds the next.
Line 1 — Personal exemption. Enter “1” for yourself.
Line 2 — Spouse. Enter “1” if you’re married and filing jointly. Enter “0” if you’re filing separately or if your spouse is filing their own IT 4 with their employer.
Line 3 — Dependents. Enter the number of dependents you’ll claim on your Ohio return. Ohio uses the federal definition, so anyone who qualifies as your dependent on your federal return counts here.
Line 4 — Total. Add Lines 1 through 3. This is the figure your employer feeds into Ohio’s withholding tables. More exemptions mean less tax comes out per pay period; fewer exemptions mean more.
Line 5 — Additional withholding. This one is optional. Enter a specific dollar amount if you want extra Ohio tax pulled from every check. It’s worth using if you have side income, investment earnings, or another situation where regular withholding won’t cover your full liability.
The number of exemptions on your IT 4 does not have to match your federal W-4. The two forms serve different tax systems and use different math.1Ohio Department of Taxation. Employee’s Withholding Exemption Certificate IT 4 Instructions
Resist the urge to inflate exemptions to bump up your take-home pay. Ohio’s 2.75% bracket begins above $26,050 and the top marginal rate is 3.125% on income over $100,000.4Ohio Department of Taxation. Annual Tax Rates Whatever isn’t withheld now becomes a balance due in April, sometimes with an underpayment penalty attached.
Section III: Claiming a Full Exemption
Section III is not for reducing your withholding. It’s for shutting it off entirely, and only a limited group of employees qualify. If any of the following describes you, check the appropriate box in Section III instead of filling in Section II:1Ohio Department of Taxation. Employee’s Withholding Exemption Certificate IT 4 Instructions
- You live in Indiana, Kentucky, Michigan, Pennsylvania, or West Virginia and work in Ohio. Ohio has reciprocity with these five states, so your wages are taxed by your home state, not Ohio.2Ohio Department of Taxation. Employer Withholding Reciprocity
- You’re an Ohio resident on active duty stationed outside Ohio. Your military pay and allowances are exempt.
- You’re a nonresident servicemember stationed in Ohio. Your military pay isn’t subject to Ohio tax.
- You’re the civilian spouse of a servicemember stationed in Ohio under orders, your legal residence is in another state, and you’re in Ohio only to be with your spouse. Your wages may be exempt under the federal Military Spouses Residency Relief Act.
- You earn less than $300 from this employer in a calendar quarter and the work isn’t part of your regular employment with them.
Some of these situations call for a specialized form in addition to, or instead of, the standard IT 4. Reciprocity claims are usually documented on Form IT 4NR.5Ohio Department of Taxation. IT 4NR Employee’s Statement of Residency in a Reciprocity State Active-duty Ohio residents stationed outside the state file Form IT 4 MIL with their finance officer.6Ohio Department of Taxation. IT 4 MIL Military Employee Exemption From Withholding Military spouses provide their employer with a copy of their spousal military ID and a signed home-state residency declaration.7Ohio Department of Taxation. Exemption from Withholding – Military Spouse Employee Ask your payroll office which form they need in your specific case.
Checking a Section III box that doesn’t apply to you can trigger penalties, so be honest.
The School District Section
Ohio has 214 school districts that levy their own income tax on residents, with rates from 0.25% to 2.00%.8Ohio.gov. School District Tax Year 2026 The IT 4 has dedicated lines for your district’s name and its four-digit identification number. Both fields are required. Writing just the name isn’t enough.9Ohio Department of Taxation. School District Income Tax
Your district is set by where you live, not where you work. If The Finder shows your home address isn’t in a taxing district, leave this section blank. If you move mid-year, file a new IT 4 so withholding starts or stops with the change of address.9Ohio Department of Taxation. School District Income Tax
Turning It In and Keeping It Current
Sign the form and hand it to your payroll or HR contact. The updated withholding should appear on your next paycheck. Keep a personal copy. If a question ever comes up about what you asked your employer to withhold, your signed copy is the record.
Ohio requires a new IT 4 whenever the information on your current one becomes incorrect or insufficient.10Ohio Department of Taxation. Employer Withholding The usual triggers are marriage or divorce, the birth or adoption of a child, a spouse starting or leaving a job, and any move, especially one that crosses a school district line. The state doesn’t set a specific deadline, but the longer you wait, the more paychecks are withheld on the wrong basis and the bigger your reconciliation at filing time.
What Happens If You Get It Wrong
Mistakes on the IT 4 divide into two kinds.
An honest overclaim of exemptions leads to underwithholding. There’s no separate penalty for the form itself, but if you end up owing more than $500 on your annual Ohio return, you may be charged interest for underpayment of estimated taxes. Ohio calculates that on Form IT/SD 2210.11Ohio.gov. 2026 Ohio Estimated Income Tax Instructions
Deliberately filing a false certificate is treated differently. Ohio Revised Code Section 5747.99 sets fines from $100 to $5,000 for violations of the state’s withholding provisions.12Ohio Legislative Service Commission. Ohio Revised Code 5747.99 Claiming a Section III exemption you know doesn’t apply, or padding Section II to zero out your withholding, is what that section is aimed at. If you’re worried about too much coming out, fill in Section II accurately and use Line 5 to adjust the rest.