January is a filing month for many businesses because December monthly returns, fourth-quarter returns, and calendar-year annual returns often converge in the same window. Depending on the state, the due date falls at the end of January or on the 20th. December is the month to confirm filing frequency, reconcile collected sales tax against deposits, and line up access to each state's portal. Due dates shift year to year and should be confirmed for the current tax year. This article is general information, not tax advice for a specific situation.
Table of Contents
- Which sales tax returns are actually due in January?
- How do I know which filing frequency each state has assigned me?
- What should I check in December before the January filings hit?
- What are the common December mistakes that turn into January problems?
- What else is due in January besides sales tax?
- What if I am already behind on sales tax filings?
- How should I plan December so January is uneventful?
- Key Takeaways
- References
Which sales tax returns are actually due in January?
January is a convergence month. A business can owe a December monthly return, an October-through-December quarterly return, and a calendar-year annual return all within the same few weeks. The exact date depends on the state and the filing frequency assigned to the account.
California's October-through-December quarterly return is due January 31, according to the California Department of Tax and Fee Administration. The January-through-December yearly return for standard sales tax accounts is also due January 31. Monthly returns run on a different rhythm: each return is due at the end of the following month.
Minnesota's December monthly and quarterly sales tax return is due January 20, according to the Minnesota Department of Revenue. For the 2025 filing year, that date was January 20, 2026.
Colorado's October-through-December quarterly return is due January 20, according to the Colorado Department of Revenue. Colorado annual returns are also due January 20. If the 20th falls on a weekend or holiday, the due date moves to the next business day.
Missouri's tax calendar lists a monthly sales and use tax return due January 2 and a final December quarterly-monthly payment due January 6, according to the Missouri Department of Revenue. Dates shift year to year and should be confirmed for the current tax year.
How do I know which filing frequency each state has assigned me?
The state assigns the filing frequency, not the business. California's Department of Tax and Fee Administration sets a frequency of quarterly prepay, quarterly, monthly, fiscal yearly, or yearly based on reported or anticipated taxable sales at registration, according to the California Department of Tax and Fee Administration.
Colorado tiers frequency by monthly collections, according to the Colorado Department of Revenue. Businesses collecting $50 or less per month may file annually. Businesses collecting under $1,100 per month may file quarterly. Businesses collecting $1,100 or more per month must file monthly.
Frequency can change as the business grows. December is the time to re-check each state account rather than assume last year's schedule still applies. A return is generally required even with zero sales. California and Colorado both require a filing for each period, even when no sales were made and no tax was collected.
What should I check in December before the January filings hit?
Reconcile sales tax collected against what was actually remitted in each state. December is the last clean month to find a gap before the January return locks in the number. A shortfall found in February is harder to unwind than one found in December.
Confirm portal logins, EFT enrollment, and payment permissions still work. Colorado requires Electronic Funds Transfer for businesses paying more than $75,000 per year in state sales tax, according to the Colorado Department of Revenue. A lapsed EFT enrollment can turn an on-time return into a late payment.
Check entity and registration details are current in every state where the business is registered. Review whether any new state crossed the nexus threshold during the year. That determines whether a January registration or return is now required. The California Department of Tax and Fee Administration assigns filing frequency at registration, so a new registration in December can create a January filing obligation.
What are the common December mistakes that turn into January problems?
Assuming a zero-sales period means no filing is a common mistake. California and Colorado both require a return every period regardless of sales activity, according to the California Department of Tax and Fee Administration and the Colorado Department of Revenue. Skipping the return creates a delinquency even when no tax is owed.
Missing the payment cut-off even when the return is filed on time is another. California payments initiated on the due date must complete before midnight Pacific time. For EFT accounts, the payment must complete before 3:00 p.m. Pacific time to be timely, according to the California Department of Tax and Fee Administration.
Forgetting weekend and holiday shifts causes missed dates. Colorado moves the due date to the next business day when the 20th falls on a weekend or holiday, according to the Colorado Department of Revenue. A calendar marked from memory may show the wrong date.
Overlooking prepayments is easy to do while focused on the Q4 return. California quarterly prepay filers have a January prepayment due February 24, according to the California Department of Tax and Fee Administration. That obligation lands shortly after the January return and is often missed.
What else is due in January besides sales tax?
Missouri's tax calendar lists a 2025 annual, monthly, and quarterly withholding, sales and use tax return due February 2, 2026, according to the Missouri Department of Revenue. Withholding and sales tax often share a filing window, so a business with employees may have two obligations landing close together.
Not every annual return is a January item. California yearly reporting on qualified purchasers and consumer use tax accounts is due April 15, according to the California Department of Tax and Fee Administration. The January deadline applies to standard sales tax accounts, not every account type.
Income tax deadlines sit later. Partnerships and S-Corps typically file by March 15, and individuals by April 15, according to TurboTax. January is when the books need to be clean enough to support those returns. Dates shift year to year and should be confirmed for the current tax year.
What if I am already behind on sales tax filings?
Being behind in one state usually means being behind in several. The sequence of catch-up matters more than speed. Filing out of order can create mismatched periods, duplicate liabilities, or missed voluntary disclosure windows.
Voluntary disclosure is often the route to getting current with a state. The process depends on the facts of each registration: when nexus began, what was collected, what was remitted, and what the state already knows. No two states handle it the same way.
Spencer Accounting Group handles Sales Tax Resolution for multi-state liabilities, including nexus review, exposure quantification, voluntary disclosure, and getting current with each state. For owners behind on returns, Back Tax Return Filing sequences catch-up work to get compliant with the least disruption. The work is unwinding a backlog, not a crisis.
How should I plan December so January is uneventful?
Build a single calendar of every state's January due date, pulled from each state's own revenue department page rather than memory. California, Colorado, Minnesota, and Missouri all publish their schedules online.
Close December books early enough that the Q4 or December return is prepared from reconciled numbers, not estimates. A return built from reconciled data is faster to file and easier to defend.
Confirm who files each return and who can authorize payment, especially for EFT accounts. California EFT payments have a 3:00 p.m. Pacific cut-off on the due date, according to the California Department of Tax and Fee Administration. Colorado EFT requirements apply above a payment threshold, according to the Colorado Department of Revenue. Dates shift year to year and should be confirmed for the current tax year.
Key Takeaways
- January is a convergence month for December monthly returns, Q4 quarterly returns, and calendar-year annual returns.
- California's October-through-December quarterly return and January-through-December yearly return are both due January 31.
- Minnesota's December monthly and quarterly return is due January 20.
- Colorado's October-through-December quarterly return and annual return are due January 20, moving to the next business day if needed.
- A sales tax return is generally required even when no sales were made in California and Colorado.
- California EFT payments initiated on the due date must complete before 3:00 p.m. Pacific time to be timely.
- Filing frequency is assigned by the state based on sales volume and should be re-checked each December.