Key takeaways
- KDOR sets the filing frequency from the prior year's tax: $1,000 or less is annual, $1,000.01 to $5,000 is quarterly, and $5,000.01 or more is monthly.
- Every period is due on the 25th of the following month, moved to the next regular workday when that date is a weekend or legal holiday.
- Local rates are added to the 6.50% state rate and remitted on the same return, and a multi-location business reports gross sales by local jurisdiction.
- A period with no sales still needs a return, filed electronically with 0 on the Gross Sales line.
Find the filing frequency before the first return
KDOR assigns the filing frequency from the tax the business collected in the preceding calendar year. The KDOR table uses annual tax bands: annual filing for $0 to $1,000.00, quarterly filing for $1,000.01 to $5,000.00, and monthly (seasonal) filing for $5,000.01 and over. KDOR's table controls. Some secondary guides show different breakpoints, such as $400 and $4,000, and those figures do not match KDOR's publication.
A new business has no filing history. KDOR sets its first-year frequency from the estimated liability on its business tax application, so keep a copy of that application in the client file with the estimate that was entered.
Frequency changes take effect January 1. KDOR says it mails a notice of proposed frequency changes before January 1, so a client whose 2026 tax crossed a band should receive a notice before the 2027 returns start. Decision rule: if the 2026 total on the returns filed crosses a band, check it against the notice. If no notice has arrived, contact KDOR before switching the client to another frequency yourself.
Worked example: a client that collected $5,000.00 of Kansas sales tax during 2026 sits at the top of the quarterly band, so its 2027 returns are quarterly. The first return covers January through March 2027. A client at $5,000.01 would move to monthly filing.
Due dates for 2026 returns, by frequency
Monthly filers are due on the 25th of the month after the reporting month. Quarterly filers are due on the 25th of the month after each quarter, so the calendar lists April 25 for January through March, July 25 for April through June, October 25 for July through September and January 25 for October through December. Annual filers are due January 25 of the following year.
The weekend and holiday rule matters in December. Christmas Day 2026 is Friday, December 25, a legal holiday, so the November 2026 monthly return moves to the next regular workday, Monday, December 28, 2026. Confirm the holiday with KDOR's calendar before the due date, because the calendar text says the due date moves to the next regular workday.
For tax year 2026, the October 2026 monthly return is due November 25, 2026. The December 2026 monthly return, the fourth-quarter 2026 quarterly return and the 2026 annual return are due January 25, 2027. A bookkeeper who calendars the 25th without checking the weekday will miss the moved dates, so put the adjusted date in the firm calendar and keep the KDOR date in the note.
File and pay through the Kansas Customer Service Center
KDOR's calendar says that by law, businesses are now required to submit their Sales, Compensating Use and Withholding Tax returns electronically. The Kansas Customer Service Center (KCSC) at kdor.ks.gov is where most businesses file. KDOR describes it as the place to file sales, use and withholding returns, make payments and update account information.
KDOR lists four payment methods. ACH Debit has KDOR debit the bank account. ACH Credit has the business initiate the payment through its bank using Form EF-101. Credit card payments go through third-party vendors and carry a convenience fee based on the tax amount. Wire transfers are also accepted. KDOR's publication says electronic tax payments must settle on or before the due date.
Failure mode: the payment is submitted on the due date but settles after it. Fix it by initiating ACH Credit several business days early and saving the bank confirmation with the filed return. Decision rule: if the client pays by card, the fee rises with the tax amount, so ask the client which method it uses before the due date and not on it.
Report local rates on the return
Kansas combines the state and local rates, so a retailer collects one total and remits it on one return. Retailers do not have to split the state and local portions of the tax they collect, because the published rates are combined. The state rate is 6.50%. Local rates are added to it, and the jurisdiction codes come from KDOR's listing of local sales tax rates by jurisdiction (KS-1700).
The form depends on the number of locations. A single-location business uses Form ST-16, the single jurisdiction form type, and enters on line 1 the total of all sales for the period, taxable and nontaxable. A business with more than one location uses Form ST-36, and enters under Gross Sales the gross receipts, taxable and nontaxable, for the month in each local jurisdiction.
Worked example with hypothetical numbers: a client has a store in one city and a second location in another city. For one month it had $60,000 of gross receipts in the first city and $40,000 in the second. Form ST-36 shows each amount under its own jurisdiction, and the total on the return is $100,000 whatever the split.
Failure mode: the point-of-sale system has one rate for the whole account. Local rates change only at the start of a calendar quarter, January 1, April 1, July 1 or October 1. Fix it with a rate table that shows each jurisdiction's effective date, and check on the first day of each quarter that the system picked up any change.
Handle food sales
As of January 1, 2025, the state sales tax on food and food ingredients is 0%. KDOR's FAQ says the full local sales tax rates on food and food ingredients are still in effect. For a 2026 return, food sales should carry only the local rate, not the 6.50% state rate.
Failure mode: a register configured before 2025 still charges the state rate on groceries. The register report then shows tax that does not match the rate table. Fix it by pulling the register's tax report for food items and comparing the tax to the rate table before the return is built.
Split the register report into food and nonfood sales before the return is prepared, so each category can be tied to its tax. A single gross figure for a mixed store hides the error until the state's figures disagree with the client's.
File zero periods and use tax on their own returns
A return is required for each reporting period, even when there is no tax to report. KDOR's example of a quarter with no sales has the seller enter 0 on the Gross Sales line and file the electronic return anyway.
Use tax goes on a separate return. KDOR says to report and pay use tax on Form CT-9U, the Retailers' Compensating Use Tax return. If the client bought taxable items for its business and did not pay sales tax on them, the use tax belongs on the CT-9U for that period, not on the ST-16 or ST-36.
Failure mode: a seasonal client sends no sales report for a quiet month, so the zero return is missed. Usual's reminder schedule can ask the client for the monthly sales report and stop once the upload is in, so the firm sees the gap before the 25th.