Iowa Estimated Tax Payments (2026)

Do you have to pay estimated taxes in Iowa?

Yes. If you're self-employed in Iowa and expect to owe $1,000 or more in Iowa income tax for 2026 after withholding, you must make quarterly estimated payments to the Iowa Department of Revenue. That's up from $200 in 2025, so fewer part-time self-employed people have to pay Iowa quarterly. Iowa taxes income at a flat 3.8%.

When are Iowa estimated taxes due in 2026?

Iowa doesn't follow the standard federal due dates in 2026. The 2026 due dates are:

• Q1, April 30, 2026

• Q2, June 30, 2026

• Q3, September 30, 2026

• Q4, February 1, 2027

How much should you set aside for Iowa estimated taxes?

Plan to set aside 20% to 25% of your net self-employment profit to cover federal and Iowa taxes combined, then confirm the exact amount with the calculator above. On $50,000 of net self-employment profit, federal self-employment tax alone is about $7,065 (15.3% on 92.35% of your earnings). On top of that you'll owe federal income tax and Iowa income tax, up to about $1,900 at Iowa's flat rate before deductions.

How do you avoid an Iowa underpayment penalty?

To avoid an Iowa underpayment penalty, pay the smaller of 90% of your 2026 Iowa tax or 100% of your 2025 tax, or 110% of last year's tax if your prior-year AGI topped $150,000, in four on-time installments. Paying the full amount late doesn't help; each installment has to be on time. You can estimate a federal underpayment penalty here.

What deductions lower your Iowa estimated taxes?

Because estimated taxes are based on your net profit, every business write-off you claim lowers what you owe each quarter. Common deductions for 1099 workers, reported on Schedule C, include the home-office deduction, car mileage, phone and internet, software, and supplies. Like the IRS, Iowa lets you deduct half of your self-employment tax, and the federal Qualified Business Income (QBI) deduction, which can remove up to 20% of your qualified business income from your federal taxes, also lowers your Iowa tax, because Iowa starts from your federal taxable income.

Keeper's 1099 tax calculator estimates your bill after deductions, and our write-off guides list the deductions for your line of work.

Do self-employed people in Iowa owe a school district surtax?

Often, yes. Many Iowa school districts add a surtax of up to 20% of your Iowa income tax, based on the district you lived in on December 31. You pay it on your Iowa return, so include it when you figure your estimated payments.

Note: Figures are current for the 2026 tax year and are for planning, not tax advice. Confirm the details with the Iowa Department of Revenue before you file.

How to file quarterly taxes in Iowa

Filing quarterly in Iowa means two separate payments each period: one to the IRS for federal tax, and one to the Iowa Department of Revenue for your state taxes. Here’s how to do it.

1. Confirm you need to pay. You owe estimated payments when tax isn’t withheld from enough of your income — 1099 or freelance work, investment income, or other untaxed income. Federal and Iowa run separate tests: the state generally requires estimated payments if you expect to owe $1,000 or more in Iowa tax after withholding and credits, subject to its safe-harbor rules.
2. Calculate your federal estimate. Use the Form 1040-ES worksheet (or tax software). Estimate your full-year income, add your federal income tax and self-employment tax, subtract anything already withheld from a paycheck, and split the rest across the year. The estimate at the top of this page gives you a starting number.
3. Calculate your Iowa estimate separately. Work out your Iowa amount on its own using Form IA 1040ES. Don’t just send part of your federal payment to the state — the Iowa calculation is separate, based on your Iowa income tax, credits, and any Iowa withholding.
4. Pay the IRS. Pay through IRS Direct Pay (or EFTPS) and choose the estimated tax / Form 1040-ES option. Select tax year 2026 and save the confirmation number. This money counts only toward your federal taxes.
5. Pay Iowa separately. Make a second payment to GovConnectIowa and select the Form IA 1040ES estimated payment for 2026. Save that confirmation too. This money counts only toward your Iowa taxes.
6. Repeat on each deadline. For 2026, federal estimated payments are due April 15, 2026, June 15, 2026, September 15, 2026, and January 15, 2027. Iowa sets its own due dates: April 30, 2026, June 30, 2026, September 30, 2026, and February 1, 2027. Don’t assume the 15th.

Steps reflect 2026 rules and are for planning, not tax advice.