Key takeaways
- Under $1,200 of tax collected in the calendar year means annual filing; $1,200 or more means monthly.
- Monthly and seasonal returns are due on or before the last day of the following month. Annual returns are due January 31 of the following year.
- Local option tax follows the delivery location, not the seller's location.
- Pay at least 90% of the correct tax by the due date, because the late-filing and late-payment penalties turn on that 90% line.
- Hold a complete Iowa Sales Tax Exemption Certificate (31-014) before treating a sale as exempt, and keep records at least three years.
Pick the schedule from the tax collected
Iowa sets the schedule from the sales and use tax a client collects in a calendar year, not from its taxable sales. Under $1,200 in a year means annual filing, and $1,200 or more means monthly. The Department's filing-frequency page states both thresholds this way.
Seasonal filing applies when a client collects $1,200 or more in four or fewer months, and the months do not have to be consecutive. The page's example is January, June, July and December. Hotel and motel, automobile rental and construction equipment taxpayers file monthly regardless of the tax collected, so check the industry before assigning annual filing.
Where the $1,200 test is silent
The threshold is tax, so the sales volume that reaches it depends on the rate charged. Run the test on year-to-date tax, using the rate actually charged on each sale. A client that sells into local option cities but tests only at the 6% state rate will understate its tax and may stay annual when it belongs on monthly.
The Department's published pages do not say how the $1,200 is measured across the year, or whether a schedule change reaches earlier months. A frequency change is requested by logging into GovConnectIowa. A monthly or annual filer that wants seasonal status must cancel its current permit and register for a new one. For a client near the line, get the Department's answer in writing before the change, and do not assume it applies retroactively.
Calendar the 2025 and 2026 due dates
Monthly and seasonal returns and payments are due on or before the last day of the following month. The October 2026 return is due on the last day of November 2026.
Annual returns are due on or before January 31 following each calendar year. For tax year 2026, that is January 31, 2027. The calendar year 2025 annual return was due January 31, 2026, so an unfiled 2025 return is past due. The filing-frequency page also sets a weekend and holiday rule for due dates, so when a due date lands on a weekend or holiday, file by the business day before. The pages describe no extension for sales tax returns.
File and pay through GovConnectIowa
The Department says Iowa sales tax is filed and remitted electronically through GovConnectIowa, and it does not mail returns. All monthly filers must file and pay electronically. A monthly filer that cannot file electronically may ask the Director for permission to file by paper, with proof of that inability. The page sets no deadline for the request, so ask before the return is due.
Annual filers are where the sources differ. The permit-change page says annual filers are not required to file electronically, while the FAQ says returns must be filed through GovConnectIowa. Set up GovConnectIowa access for every annual client anyway.
A client with no sales still has to file. The FAQ says, "Yes, if you had no sales for your filing period, you must still file your return showing $0 sales." Put the $0 return on the calendar as a recurring item.
Source local option tax to the delivery location
The state rate is 6%. Many cities and counties also have a 1% local option tax, and it applies only where delivery occurs in a local option jurisdiction. The Department says where tangible personal property is delivered determines whether a sale is taxable, and if delivery does not occur in a local option jurisdiction, local option tax is not due. Local option sales tax is remitted for the tax period in which the property is delivered, and the tax is due at delivery even if the customer has not paid.
If the seller transfers the goods to a common carrier or the U.S. Postal Service, the Department says delivery occurs at the customer's location. An FOB designation does not affect sourcing, including local option tax, so an FOB term on the invoice will not move a sale into or out of a local option city.
Johnson County changes effective July 1, 2026
The Department lists five new local option impositions in Johnson County (#52), effective July 1, 2026: Coralville, Iowa City, North Liberty, Oxford and Shueyville. Check each delivery date against July 1, 2026, because the new imposition starts on that date.
The page was published June 18, 2026, and it reports Sunset Date Changes (0), so it lists no end date for the Johnson County change. A November 2026 delivery to a Coralville address therefore carries the 1%.
Build the return from a jurisdiction-split ledger
Split the monthly ledger into four buckets: taxable sales delivered in a local option jurisdiction, taxable sales delivered outside one, exempt sales with a completed certificate, and exempt sales without one. The local tax depends on the delivery city. As a worked example, a $10,000 sale delivered to a Coralville address in November 2026 carries $600 of state tax at 6% and $100 of local option tax at 1%, or $700 in total. The same sale delivered outside a local option city carries $600. A sale tagged to the wrong city moves $100 of tax without changing the total sales figure.
Tie the buckets to the sales ledger and the payment processor report every month. If the totals differ, work the difference before the due date. File on time with the best supportable figures, pay at least 90% of the tax you expect, and amend afterward if the reconciliation changes the result. Common causes of a difference are a refund, a sale booked to the wrong month or a tax-included price that was not backed out. Map the buckets to the current return in GovConnectIowa.
Document exempt sales for the audit
The Department's guide says a seller must obtain a properly completed Iowa Sales Tax Exemption Certificate (31-014) from any purchaser claiming exemption. The obligation sits with the seller, so a missing certificate is the client's gap to close, not something a buyer's later word fixes.
If a buyer claims a resale exemption, ask for the 31-014 before the first invoice and file it with that invoice. A client can be asked in one line: "Please send a completed Iowa Sales Tax Exemption Certificate (31-014) before our first invoice so we can record your purchases as exempt." Until a complete certificate is on file, treat the sale as taxable.
The guide says records are required to be maintained for at least three years, and the Department may request records for a longer period if returns have never been filed. It may audit a return anytime within three years. The period for audit is unlimited if a return was filed falsely or fraudulently, or if no return was filed, so a client that never filed should keep its exemption and sales records with no planned end date.
Fix the errors that cause amended returns and penalties
Source the local rate to the delivery address, never the store address. Tag each sale with its delivery city at order entry, calculate the local rate from that tag, and check it against the Department's jurisdiction list before preparing the return. Resolve the delivery city before the return is due by checking the shipping address or order record. Report every taxable sale in the period it was delivered. If the city cannot be confirmed by the due date, use the best-supported delivery address, keep the sale on the return, and amend later if needed.
The late-filing penalty is 5% of the unpaid tax when a return is not filed by the due date and less than 90% of the correct tax is paid. A separate late-payment penalty of an additional 5% applies when less than 90% of the correct tax is paid by the due date, and both can apply. Separately, a 5% penalty of the tax due applies when payment is not received electronically, and another 5% applies when return information is not reported through GovConnectIowa. A taxpayer that keeps failing to file 90 days after a Department demand letter faces a $1,000 penalty. Check the current interest rate on revenue.iowa.gov before quoting interest to a client.