If you lived in DeKalb County, Indiana on January 1, you owe a local income tax of 2.13% on your Indiana adjusted gross income for the entire tax year, on top of the 2.95% state rate.1Indiana Department of Revenue. How to Compute Withholding for State and County Income Tax2Indiana Department of Revenue. Rates Fees and Penalties There is no separate county return. The tax is calculated and paid as part of your Indiana state filing.
The Rate and the January 1 Rule
DeKalb County carries county code 17 on Indiana tax documents, and its local rate is 2.13% of Indiana adjusted gross income.1Indiana Department of Revenue. How to Compute Withholding for State and County Income Tax The rate you owe is fixed by where you lived on January 1 of the tax year. Move from DeKalb to Allen County on January 2 and you still owe DeKalb’s rate for the full year. There is no proration for a mid-year move.
Because employers withhold county tax from each paycheck based on the address you give them, filing an updated Form WH-4 at the start of any year you have moved keeps your withholding aligned with what you actually owe.3Indiana Department of Revenue. Indiana 2025 IT-40 Full-Year Resident Individual Income Tax Booklet
Who Owes It
Any DeKalb County resident on January 1 owes the 2.13% rate on their Indiana adjusted gross income, regardless of where their employer is located.1Indiana Department of Revenue. How to Compute Withholding for State and County Income Tax
If you live out of state and commute into DeKalb County, the picture changes. Indiana has reciprocal agreements with Kentucky, Michigan, Ohio, Pennsylvania, and Wisconsin that cover wages, salaries, tips, and commissions, so residents of those states report wage income to their home state rather than Indiana. Those agreements do not cover local income tax. An Ohio resident working in DeKalb County still owes DeKalb’s nonresident local tax on that income.4Indiana Department of Revenue. Income Tax Information Bulletin 28
Social Security benefits are not subject to Indiana state or local income tax. Any Social Security income on your federal return is subtracted on your Indiana return before the county rate applies. Military retirement pay and railroad retirement benefits get similar treatment.
How to File
Full-year residents file Form IT-40 and attach Schedule CT-40, the county tax worksheet. On Schedule CT-40 you enter county code 17 as your county of residence on January 1 and multiply your Indiana adjusted gross income by 2.13% to produce the county tax owed.5Indiana Department of Revenue. Schedule CT-40 County Tax Schedule for Indiana Residents The county tax flows through to the IT-40 and is paid alongside your state tax.
The deadline for the 2025 tax year is April 15, 2026. Indiana grants an extension through November 16, 2026, but interest still runs on any unpaid balance from April 15 forward.6Indiana Department of Revenue. Extension of Time to File
Filing Electronically
The Indiana Taxpayer Information Management Engine (INTIME) is the state’s online portal for filing, paying, and managing your account.7Indiana Department of Revenue. INTIME E-filed returns generate an immediate confirmation and refunds process faster than on paper.
Filing on Paper
Paper returns go to one of two addresses depending on whether a payment is enclosed. With a payment: P.O. Box 7224, Indianapolis, IN 46207-7224. Without a payment: P.O. Box 40, Indianapolis, IN 46206-0040.8Indiana Department of Revenue. Mail in Tax Forms Tracked mail protects you if there is any dispute about the postmark.
Estimated Payments If Withholding Falls Short
If you expect to owe $1,000 or more in combined state and county tax that is not covered by withholding, you must make quarterly estimated payments.9Indiana Department of Revenue. Estimated Payments This typically applies to self-employed workers, freelancers, landlords, and retirees with pension income.
Installments are due April 15, June 15, September 15, and January 15 of the following year. If a due date falls on a weekend or holiday, it moves to the next business day. You can pay through INTIME or mail Form IT-40ES vouchers to P.O. Box 7223, Indianapolis, IN 46207-7223.8Indiana Department of Revenue. Mail in Tax Forms Missing or underpaying an installment triggers a 10% penalty on the shortfall for that period.9Indiana Department of Revenue. Estimated Payments
You can avoid the underpayment penalty if your withholding plus estimated payments equals at least 90% of your current year’s tax or 100% of last year’s tax. If your federal adjusted gross income exceeds $150,000 ($75,000 if married filing separately), that safe harbor rises to 110% of the prior year’s tax.
Deductions That Lower Your County Tax
Because the 2.13% rate applies to Indiana adjusted gross income, anything that reduces that number also reduces your county tax. The renter’s deduction lets you subtract up to $3,000 of rent paid on your principal Indiana residence during the year, or $1,500 if married filing separately.10Indiana Department of Revenue. Deductions Indiana also allows personal exemptions of $1,000 per taxpayer, $1,000 per spouse on a joint return, and additional exemptions for dependents.
Penalties and Interest
Late filing or underpayment carries real costs, and they apply to the county portion of your bill the same way they apply to the state portion.
- Failure to file: 20% of the tax due, rising to 100% if the Department of Revenue determines fraud.
- Failure to pay: 10% of the unpaid balance, or $5, whichever is greater.
- Underpayment of estimated tax: 10% of the shortfall for each installment period.
Unpaid balances also accrue interest at 7% annually for calendar year 2026, a rate the state recalculates each year.11Indiana Department of Revenue. Departmental Notice 3 – Interest Rates for Calendar Year 2026 A $2,000 unpaid county tax balance would generate $140 in annual interest on top of any penalty.2Indiana Department of Revenue. Rates Fees and Penalties
If you receive a notice from the Department of Revenue, respond promptly. The state cross-references returns against employer-reported withholding, and unresolved notices can escalate to collections.