To file Iowa Form IA 1040, finish your federal return first, carry your federal taxable income onto the Iowa form, apply Iowa’s adjustments and credits, calculate tax at the 2026 flat rate of 3.8 percent, and submit the return electronically or by mail by April 30.1Iowa Department of Revenue. IDR Announces 2026 Individual Income Tax and Interest Rates The IA 1040 is Iowa’s individual income tax return, used by residents, part-year residents, and nonresidents with Iowa-source income.
Do You Have to File
Iowa Code Section 422.13 sets filing thresholds based on your status and age. For the 2025 tax year, filed in 2026, you must file an IA 1040 if your net income exceeds:2Iowa Department of Revenue. Intro 3 – Who Must File
- $9,000 if single or married filing separately, or $24,000 if you were 65 or older on December 31, 2025.
- $13,500 if married filing jointly, head of household, or qualifying surviving spouse, or $32,000 if either spouse was 65 or older on December 31, 2025.
- $5,000 of Iowa taxable income if someone claims you as a dependent.
Part-year residents and nonresidents must file once their Iowa-source net income reaches $1,000. Iowa-source income includes wages earned in Iowa, rental income from Iowa property, self-employment income from work performed in the state, Iowa unemployment benefits, and Iowa gambling winnings.2Iowa Department of Revenue. Intro 3 – Who Must File
One boundary worth noting: Iowa has a reciprocal agreement with Illinois covering wages and salary only. An Iowa resident working in Illinois pays Iowa tax on those wages, and an Illinois resident working in Iowa pays Illinois tax. Other Iowa-source income, such as gambling winnings and unemployment compensation, remains taxable to Iowa regardless of where the recipient lives. Illinois residents working in Iowa should file form IA 44-016 with their employer so Illinois withholding applies.3Iowa Department of Revenue. Iowa – Illinois Reciprocal Agreement
Even if your income sits below the thresholds, file anyway when an employer withheld Iowa tax or you qualify for a refundable credit like the Iowa Earned Income Tax Credit. The state will not send that money without a return.
What to Have in Hand Before You Start
Pull the following together first:
- Social Security numbers for yourself, your spouse if filing jointly, and any dependents.
- A completed federal Form 1040. Iowa starts from federal taxable income, so the federal return has to be done first, even if you have no federal filing requirement.
- W-2s from every employer and 1099 forms for interest, dividends, retirement distributions, and other reported income.
- Records for any Iowa-specific adjustments, such as retirement income documentation or ISave 529 contribution statements.
The current IA 1040 and its instructions are on the Iowa Department of Revenue’s forms page.4Iowa Department of Revenue. Forms – Individual Income Tax
Filling Out the Return
Filing Status
Your Iowa filing status must match your federal filing status.5Iowa Department of Revenue. Intro 5 – Filing Status Jointly on the federal return means jointly in Iowa. Married couples filing separately must still combine their incomes to test the low-income exemption thresholds.
Starting Point and Rate
The IA 1040 begins with your federal taxable income, which is the amount from your federal Form 1040 after the standard or itemized deduction has been applied. It is not federal adjusted gross income. Iowa then applies its own additions and subtractions to produce Iowa taxable income, and for 2026 that income is taxed at a flat 3.8 percent.1Iowa Department of Revenue. IDR Announces 2026 Individual Income Tax and Interest Rates
Two Common Iowa Subtractions
Starting with tax year 2023, Iowa fully excludes qualifying retirement income from state tax for eligible taxpayers, replacing the older cap of $6,000 for single filers and $12,000 for married couples. If you are generally 55 or older, disabled, or a surviving spouse, your qualifying pension, IRA, and 401(k) distributions are completely excluded from Iowa taxable income.6Iowa Department of Revenue. Retirement Income Tax Guidance
Account owners of ISave 529 plans (formerly College Savings Iowa) can deduct contributions. The 2026 limit is $6,100 per beneficiary account, and each account owner takes the deduction separately. Married parents who each own an account for the same child can each deduct up to $6,100.7State Treasurer of Iowa. ISave 529
Credits That Reduce What You Owe
Several Iowa credits apply after you calculate the tax, and some are refundable, meaning they can produce a refund even when your liability is zero.
The Iowa Earned Income Tax Credit is 15 percent of the federal EITC you claimed, and it is fully refundable. Multiply your federal EITC by 0.15 and enter the result on the appropriate line.8Iowa Department of Revenue. Iowa Earned Income Tax Credit
The refundable Child and Dependent Care Credit is available to taxpayers with Iowa taxable income under $90,000, calculated as a percentage of the federal child and dependent care credit that ranges from 75 percent at the lowest incomes down to 30 percent near the cap. Taxpayers with children between ages three and five may instead claim the Early Childhood Development Tax Credit, which is 25 percent of the first $1,000 in qualifying preschool and educational expenses per child. You claim one or the other, not both.9Iowa Department of Revenue. Line 24 – Child and Dependent Care Credit or Early Childhood Development Tax Credit
If you are a part-year resident or nonresident, complete Schedule IA 126. It calculates a credit based on the ratio of Iowa-source income to total income so you are not taxed on income earned outside the state.10Iowa Department of Revenue. Line 13 – Credit for Nonresident or Part-Year Resident
How to Submit the Return
Electronic Filing
The Iowa Department of Revenue offers free electronic filing for taxpayers who qualify, along with paid e-file options through approved software vendors.11Iowa Department of Revenue. Individual Taxes E-filed returns typically enter the department’s system within about a week, and most third-party software that handles your federal return will transmit the Iowa return at the same time.
Paper Filing
To file on paper, mail the completed return to:
Iowa Income Tax Document Processing
PO Box 9187
Des Moines, IA 50306-918712Iowa Department of Revenue. Mailing Addresses
If you owe tax, include a check or money order with the IA 1040V payment voucher. Paper returns process more slowly than electronic ones.
Signing
An unsigned return will not be processed and no refund will be issued until the signature arrives. On a joint return, both spouses must sign.13Iowa Department of Revenue. Step 10 – Signature
Paying a Balance Due
If you owe, the Iowa Department of Revenue accepts:14Iowa Department of Revenue. EasyPay Iowa
- Credit or debit card online through GovConnectIowa, with a separate convenience fee from the payment provider.
- ACH debit from your bank account, also through GovConnectIowa. If your bank has an ACH debit block, you will need to give it the department’s Company ID.
- Check or money order mailed with the IA 1040V voucher.
- Cash in person at the Iowa Department of Revenue office in Des Moines.
Individual income tax cannot be paid by ACH credit; that option is reserved for certain business taxes.
Deadline and Automatic Extension
Iowa individual income tax returns are due April 30, a full month after the federal deadline.11Iowa Department of Revenue. Individual Taxes
Iowa has no separate extension form, and a federal extension does not extend the Iowa deadline. You get an automatic extension to October 31 as long as you have paid at least 90 percent of your total tax liability by April 30. To check, multiply your total tax (IA 1040, line 20) by 0.90; if the result is equal to or less than the total payments on line 30, you qualify. No paperwork is required.15Iowa Department of Revenue. Note – Additional Information
The extension waives the late-filing penalty only. Interest still accrues on any unpaid balance after April 30.
Checking Your Refund
The department’s “Where’s My Refund” tool shows your return’s status. For e-filed returns, allow about a week for the information to appear. Anticipated refund processing is 30 days from the date the return is received, and paper returns can take longer.16Iowa Department of Revenue. Where’s My Refund
What Late Filing or Late Payment Costs
Penalties stack up fast:17Iowa Department of Revenue. Penalties and Interest Rates
- Late filing: 5 percent of the unpaid tax if you did not file by the due date and paid less than 90 percent of the correct tax.
- Late payment: another 5 percent of the unpaid tax if less than 90 percent was paid by the due date.
- Both can apply at once, producing a combined 10 percent penalty on the unpaid balance.
- Audit deficiency: 5 percent of any additional tax found during an exam.
- Fraud: 75 percent of the fraudulent amount or unpaid tax. This penalty cannot be waived.
Interest runs on any unpaid balance from the due date. The 2026 annual rate is 10 percent, or 0.8 percent per month.17Iowa Department of Revenue. Penalties and Interest Rates At that rate, paying what you can by April 30, even an estimate, is almost always cheaper than waiting until you finish the return.