Iowa sales tax is due on the last day of the month after your reporting period ends. Most businesses file monthly, so January’s tax is due February 28, February’s is due March 31, and so on. Businesses that collect less than $1,200 in sales and use tax per year file just once, with the return due January 31 of the following year.1Department of Revenue. Filing Frequency and Return Due Dates Iowa does not offer a quarterly option for sales tax, even though it exists for other state taxes.
Which Filing Schedule Applies to You
The Iowa Department of Revenue uses one number to sort businesses: $1,200 in annual sales and use tax liability. Owe that much or more in a calendar year and you file monthly. Owe less and you file annually.2Iowa Administrative Code. Iowa Administrative Code 701-202.1 Sales and Use Tax Filing You can also elect to file monthly even if your liability qualifies you for annual filing.
Four categories of business must file monthly regardless of how little they collect: hotels, motels, auto rental companies, and construction equipment rental businesses. Even annual liability well below $1,200 does not get you off the monthly schedule in those lines of work.1Department of Revenue. Filing Frequency and Return Due Dates
Seasonal filers are a narrow third category. If you owe $1,200 or more but operate only four months or fewer per year, you file returns only for the months you actually operate. A fireworks stand that opens around the Fourth of July is the standard example. Each seasonal return is still due by the last day of the following month.1Department of Revenue. Filing Frequency and Return Due Dates
Monthly Due Dates
Monthly filers submit the return and payment by the last day of the month following the period being reported.3Iowa Legislature. Iowa Code 423.31 Filing of Sales or Use Tax Returns and Payment So:
- January sales tax is due February 28 (February 29 in a leap year)
- February is due March 31
- March is due April 30
- And so on through December, which is due January 31 of the next year
If the last day of the month falls on a Saturday, Sunday, or legal holiday, the deadline moves to the next business day.4Iowa Legislature. Iowa Code 421.9A Check a calendar at the start of each year so a weekend shift does not catch you off guard.
Electronic submission is mandatory for monthly filers. Payments transmitted through GovConnectIowa must go through by 11:59 p.m. central time on the due date to count as timely.5Department of Revenue. GovConnectIowa Submitting a paper return when you are required to e-file carries its own 5% penalty, separate from any late-payment penalty.6Department of Revenue. Penalties and Interest Rates
The Annual Deadline
If your sales and use tax liability stays under $1,200 for the year, you file one return covering the whole calendar year. It is due January 31 of the following year, so your 2026 return is due January 31, 2027.1Department of Revenue. Filing Frequency and Return Due Dates Annual filers can submit electronically through GovConnectIowa or send a paper return. The weekend and holiday shift rule applies here too.
What Late Filing Costs
Miss the deadline and Iowa adds a 5% penalty on the unpaid tax, as long as you paid less than 90% of the correct amount by the due date. If you were required to file electronically and did not, a separate 5% penalty applies on top of that.6Department of Revenue. Penalties and Interest Rates
Interest runs at 10% per year for 2026, which works out to 0.8% per month. Each partial month counts as a full month, so being one day into a new month costs you the same as being 29 days into it.6Department of Revenue. Penalties and Interest Rates
The consequences escalate beyond missed deadlines when conduct turns willful. Willfully attempting to evade Iowa sales tax is a class “D” felony. Selling at retail without a valid sales tax permit is a serious misdemeanor, and continuing to sell after your permit has been revoked is an aggravated misdemeanor. The state has six years to commence prosecution for these offenses.7Iowa Legislature. Iowa Code Chapter 423 – Section 423.40 Penalties, Offenses, Limitation
When Out-of-State Sellers Have to Start Filing
Businesses outside Iowa must collect Iowa sales tax once gross revenue from Iowa sales reaches $100,000 in the current or prior calendar year. Iowa uses no separate transaction-count threshold.8Department of Revenue. Remote Sellers and Marketplace Facilitators
The start date catches sellers off guard. You do not have to collect on the transaction that pushes you over $100,000. You begin collecting on the first day of the next calendar month that starts at least 30 days after you crossed the threshold, and you keep collecting through the end of that year and the entire following calendar year.8Department of Revenue. Remote Sellers and Marketplace Facilitators From that point forward, you file on the same monthly or annual schedule as any Iowa retailer, based on how much tax the Department expects you to collect.
If You Sell Through a Marketplace
If all your Iowa sales run through a marketplace facilitator like Amazon, Etsy, or Walmart Marketplace, and the facilitator makes or facilitates $100,000 or more in Iowa sales, the platform collects and remits the tax. You do not need an Iowa sales tax permit and you do not file Iowa sales tax returns for those sales.8Department of Revenue. Remote Sellers and Marketplace Facilitators Iowa law does not let the facilitator and seller contract around that responsibility.
If you also make direct sales to Iowa customers outside the marketplace, those direct sales are yours to permit, collect on, and report. Your marketplace sales still count toward the $100,000 nexus threshold that triggers your own filing obligation on the direct side.